BABY'S HOW-TO SUDOKU
After seeing people struggle at the Quilting Game on Colors, I thought I would try and help some people out with a how-to guide. I've spent a lot of time this week teaching my family members how to do these puzzles, so in theory doing one on the internet will be easier, because computers have an undo button and no white out fumes.
To start off, I'm going to be using the puzzle from Quilting 50 - the round is already closed and prizes passed out, so it seemed like a fine choice. If you do not understand sudoku and you want to follow along, save this copy and fill it in as I go.

And since I want to try and make this as easy as possible to explain, I've color coded and labeled every row, column, and section and thickened the lines that separate each section/cube.

Sorry if the brown and greyed out sections look fairly similar, my screen shows them clearly enough but I can tell they are close enough to be awkward.
The basic explanation of a sudoku is: The numbers 1 through 9 (in this case, the nine colors red, orange, yellow, green, blue, purple, brown, black and gray) can only appear once in every row, every column, and every cubed section.
But what does that mean? Because there is already a red square in row 1, we cannot put another red in that row. The red square is in the red cube, so we cannot put another red in that cube. And we cannot drop a second red in column B. To show you where red cannot go, I could mark it like this:

This rule applies to every color, every cube, every row and every column. That's the trick to this puzzle. You have to find the place where only that one color can belong.
Looking just at columns DEF, let's mark where red cannot go.

Now, using what is available in the greyed cube, let's finish marking rows 789.

There is only one square left open in the brown cube, and that means that is the place red belongs.

Sometimes it's easier to spot where certain colors belong! Without any help from the rest of the puzzle, columns ABC tell us on their own where to put the third brown square.

Since there's only one spot left open in column A, we know where to put the brown. Let's try to fill a couple more spots like this.
I like to find the easiest places first to build off of. Using that last image as our example, take a quick look at columns DEF. There are two purple squares there, so we know which column has to house the last purple square. There are two available squares in that column, but not when we look at where the rows 789 intersect.

The process of elimination is key to completing this puzzle and claiming prizes. There are always going to be "maybe" spots - spots where this color could go, but there's no reason it couldn't also fit in an open spot somewhere else on the row or column. While you can put a spot of color in these squares to help you, I like to move definitively in the Colors game, so that's the technique I will show you here. (It should also work for easy and low level sudoku as well.)
We can use the same blocking out process in DEF to find the last orange square, too.

Now, even though there is only one gray square in rows 123, we can find where to put a second. It's important to look over the whole puzzle and not try to complete it cube by cube! We'll try to keep moving as we go.

Good, we're really picking up steam now. I see another easy fill in spot in the gray cube, so I'll show you how I got it.

More good news: That orange we just placed will help us finish off GHI.

With that there, we see that there's only one orange square left to place in our cube. All you have to do is look ABC and 789 to get it!

We're officially done with orange now, but as long as we're in the purple cube, let's put in the last gray square.

We can even do a purple while we're in here.

Now, as I mentioned in the very beginning: Only one color can belong in every column, row and cube. We're going to use this to finish off Column A, starting with red. Remember: We are only filling in column A, so since the rest of the puzzle comes later, we're not going to look at it yet.

So far we have red, orange, yellow, purple, black, brown and gray. That means that green and blue are the last two colors to fill in, and they've just told us where they cannot go.

We're doing good!
(I know that I make it look particularly easy in this walkthrough, but I'm looking at every row/column/cube before I make any moves to show you what is the simplest move to make at any time.)
Anyway, here's our puzzle so far:

I'd really like to fill more in elsewhere so we can keep completing things There's a space available in the gray cube, so I'll take it.

The placement of this green will allow us to finish off GHI, so let's so ahead and do that.

Now, the gray cube is nearly fill. It just needs gray and black. By looking at column I, we know where the black square cannot go to complete the cube - so, just like before, we can finish off one segment in a quick blow.

So we'll fill in those two squares to finish off the cube.

The more we add, the easier the puzzle becomes to finish off. We can for sure finish the purple cube now, since it's only missing black and yellow and we know where not to put black, so let's see how and then do it.

With the missing pieces added in, it becomes

this. We still have yellow in our fill in bucket (or I do, at least), and since 7 and 8 have their yellow already and 9 only has one free space left ...

... well, we know where to put it. But does putting this yellow in here give us enough information to put another yellow somewhere else in the puzzle?

It sure does!
(Sorry about the hideous yellow everywhere.)
We can also finish with yellow in rows 123 utilizing our process of elimination.

We can't finish yellow off in the puzzle completely just yet. There isn't enough information to tell us where the last couple go, but we are only missing two colors in column I. We need only place red and purple to finish it, so let's see.

Well, purple could fill either hole. But red tells us another story; it knows exactly where it can go, so purple can fall in line after we've placed it.

There's still a lot to go, but we're gaining steadily. I've looked over a few rows and columns, and I see a nice open spot in rows 123.
Hopefully, you also see it - but in case you don't, I'll show you.

But how can you tell if filling in this one space will help in other spots on the puzzle? Well, we're getting closer now, so every spot we fill in is helping us more and more. Since there are still cubes that need gray, it's important to take a look and see if that square we just filled in will help us.
Horizontally we're fine; we know we finished the grays in 123. So let's look down at DEF, since we're in the middle of the puzzle.
There's a lot of empty spaces in white cube, and a few down in the brown. But when we look at 789, we see there's just one spot left for us to take.

We're going to shift gears slightly and look up at rows 123 quickly. Now that we have a gray in the orange cube, we're only missing one square in row 2. That's an easy fill: What color is not yet represented in that row?

(Hint: It's blue.)
4, 5 and 6 still have a lot of open areas, but don't worry about that just yet. Everything is going to fall into place. There are a couple other rows that are only missing two spots, so let's look at those.
Row 1 is missing black and brown, but we can't tell which goes where just yet. That's okay; we'll get back to it soon enough.
Row 8 is missing black and green. We don't know where black goes on its own ... but we can figure out green, and that'll tell us where black fits.

That finishes off not only row 8, but also the brown cube. High fives all around.
Column F is only missing two colors now; black and blue.

Let's go ahead and finish that off and take a look at what we have.

We're close in a lot of places. That's exciting - but many of them are either/or squares, which is a disappointment. But, since we can easily see two blacks in rows 123... well, 2 and 3 have theirs, so only 1 is missing out. Can we place it? It can't go in E, since the orange cube already has a black - so it's designated over to G.
Seeing as how that gives us just one empty box in the yellow cube, I'll put in the missing color, brown.

What next? The easiest place to play is row 1. Only one square is empty! Brown, the missing color, goes there.
This is going to leave us with one empty spot in the orange cube, so we can put blue in while we're there.

Where to now? D has one square left. It's a brown!

It's time to do a little work again. Don't worry, this won't be too hard. Even though there aren't any neat "one spot left" spaces left, we did just put in a brown. Maybe that will help us put another in.

Rad cool, we've got one! Now we're completely done with browns, too. This also gives us just two squares left in column H, so let's look at those too. We need yellow and blue to finish it off.

So we know exactly where to put the missing squares in that column. And since that also puts a blue in row 5, and we already have 4's placed, let's check out row 6.

Excellent.
There are a lot of places we can move from there, but me personally, I am going up column C since that's where we just played. We still need a red, green and purple. Well, I can't place green and purple yet, but red is possible!

A second red in 456 is going to tell us where the last red of the puzzle goes, too.

My line kinda smudged the square, but you see it, yes? Row 6 only allows us one spot.
The red there means that column G only has two spots left to fill. Gray could go in either place, but purple can only go in row 5 - see, row 4 has purple already.

Almost done! You are getting it! YOU CAN DO IT.
Row 4 has a pair of holes; yellow and green. Yellow is obvious, which makes green obvious. Same old, same old.

Let's go to column C next, because this is my write up and that's where I feel like going (you're not my real mom, so you can't make me go somewhere else, sorry to say).
C is missing green and purple. Or it was, before I looked twice.

We can certainly finish off the red cube now, since it's only missing one square. Tuck that little green away and take a look around.
5 across needs black and gray. Easy as pie; gray can't go here.

... so it goes in the other open 5 spot. And then black goes in the last space in 5 across.
This leaves us just with two open spaces in the entire puzzle.

The green cube is missing purple; so is column B. Fill that in, and you just have to fill in the loneliest black square ever in the white, center cube.

DONE. Complete and total sudoku victory.
Hopefully I did a decent enough job of explaining why I moved where I did, and how I knew not to move, that everyone who skipped this round can go ahead and try the new round that just went up. ;A;b
To start off, I'm going to be using the puzzle from Quilting 50 - the round is already closed and prizes passed out, so it seemed like a fine choice. If you do not understand sudoku and you want to follow along, save this copy and fill it in as I go.

And since I want to try and make this as easy as possible to explain, I've color coded and labeled every row, column, and section and thickened the lines that separate each section/cube.

Sorry if the brown and greyed out sections look fairly similar, my screen shows them clearly enough but I can tell they are close enough to be awkward.
The basic explanation of a sudoku is: The numbers 1 through 9 (in this case, the nine colors red, orange, yellow, green, blue, purple, brown, black and gray) can only appear once in every row, every column, and every cubed section.
But what does that mean? Because there is already a red square in row 1, we cannot put another red in that row. The red square is in the red cube, so we cannot put another red in that cube. And we cannot drop a second red in column B. To show you where red cannot go, I could mark it like this:

This rule applies to every color, every cube, every row and every column. That's the trick to this puzzle. You have to find the place where only that one color can belong.
Looking just at columns DEF, let's mark where red cannot go.

Now, using what is available in the greyed cube, let's finish marking rows 789.

There is only one square left open in the brown cube, and that means that is the place red belongs.

Sometimes it's easier to spot where certain colors belong! Without any help from the rest of the puzzle, columns ABC tell us on their own where to put the third brown square.

Since there's only one spot left open in column A, we know where to put the brown. Let's try to fill a couple more spots like this.
I like to find the easiest places first to build off of. Using that last image as our example, take a quick look at columns DEF. There are two purple squares there, so we know which column has to house the last purple square. There are two available squares in that column, but not when we look at where the rows 789 intersect.

The process of elimination is key to completing this puzzle and claiming prizes. There are always going to be "maybe" spots - spots where this color could go, but there's no reason it couldn't also fit in an open spot somewhere else on the row or column. While you can put a spot of color in these squares to help you, I like to move definitively in the Colors game, so that's the technique I will show you here. (It should also work for easy and low level sudoku as well.)
We can use the same blocking out process in DEF to find the last orange square, too.

Now, even though there is only one gray square in rows 123, we can find where to put a second. It's important to look over the whole puzzle and not try to complete it cube by cube! We'll try to keep moving as we go.

Good, we're really picking up steam now. I see another easy fill in spot in the gray cube, so I'll show you how I got it.

More good news: That orange we just placed will help us finish off GHI.

With that there, we see that there's only one orange square left to place in our cube. All you have to do is look ABC and 789 to get it!

We're officially done with orange now, but as long as we're in the purple cube, let's put in the last gray square.

We can even do a purple while we're in here.

Now, as I mentioned in the very beginning: Only one color can belong in every column, row and cube. We're going to use this to finish off Column A, starting with red. Remember: We are only filling in column A, so since the rest of the puzzle comes later, we're not going to look at it yet.

So far we have red, orange, yellow, purple, black, brown and gray. That means that green and blue are the last two colors to fill in, and they've just told us where they cannot go.

We're doing good!
(I know that I make it look particularly easy in this walkthrough, but I'm looking at every row/column/cube before I make any moves to show you what is the simplest move to make at any time.)
Anyway, here's our puzzle so far:

I'd really like to fill more in elsewhere so we can keep completing things There's a space available in the gray cube, so I'll take it.

The placement of this green will allow us to finish off GHI, so let's so ahead and do that.

Now, the gray cube is nearly fill. It just needs gray and black. By looking at column I, we know where the black square cannot go to complete the cube - so, just like before, we can finish off one segment in a quick blow.

So we'll fill in those two squares to finish off the cube.

The more we add, the easier the puzzle becomes to finish off. We can for sure finish the purple cube now, since it's only missing black and yellow and we know where not to put black, so let's see how and then do it.

With the missing pieces added in, it becomes

this. We still have yellow in our fill in bucket (or I do, at least), and since 7 and 8 have their yellow already and 9 only has one free space left ...

... well, we know where to put it. But does putting this yellow in here give us enough information to put another yellow somewhere else in the puzzle?

It sure does!
(Sorry about the hideous yellow everywhere.)
We can also finish with yellow in rows 123 utilizing our process of elimination.

We can't finish yellow off in the puzzle completely just yet. There isn't enough information to tell us where the last couple go, but we are only missing two colors in column I. We need only place red and purple to finish it, so let's see.

Well, purple could fill either hole. But red tells us another story; it knows exactly where it can go, so purple can fall in line after we've placed it.

There's still a lot to go, but we're gaining steadily. I've looked over a few rows and columns, and I see a nice open spot in rows 123.
Hopefully, you also see it - but in case you don't, I'll show you.

But how can you tell if filling in this one space will help in other spots on the puzzle? Well, we're getting closer now, so every spot we fill in is helping us more and more. Since there are still cubes that need gray, it's important to take a look and see if that square we just filled in will help us.
Horizontally we're fine; we know we finished the grays in 123. So let's look down at DEF, since we're in the middle of the puzzle.
There's a lot of empty spaces in white cube, and a few down in the brown. But when we look at 789, we see there's just one spot left for us to take.

We're going to shift gears slightly and look up at rows 123 quickly. Now that we have a gray in the orange cube, we're only missing one square in row 2. That's an easy fill: What color is not yet represented in that row?

(Hint: It's blue.)
4, 5 and 6 still have a lot of open areas, but don't worry about that just yet. Everything is going to fall into place. There are a couple other rows that are only missing two spots, so let's look at those.
Row 1 is missing black and brown, but we can't tell which goes where just yet. That's okay; we'll get back to it soon enough.
Row 8 is missing black and green. We don't know where black goes on its own ... but we can figure out green, and that'll tell us where black fits.

That finishes off not only row 8, but also the brown cube. High fives all around.
Column F is only missing two colors now; black and blue.

Let's go ahead and finish that off and take a look at what we have.

We're close in a lot of places. That's exciting - but many of them are either/or squares, which is a disappointment. But, since we can easily see two blacks in rows 123... well, 2 and 3 have theirs, so only 1 is missing out. Can we place it? It can't go in E, since the orange cube already has a black - so it's designated over to G.
Seeing as how that gives us just one empty box in the yellow cube, I'll put in the missing color, brown.

What next? The easiest place to play is row 1. Only one square is empty! Brown, the missing color, goes there.
This is going to leave us with one empty spot in the orange cube, so we can put blue in while we're there.

Where to now? D has one square left. It's a brown!

It's time to do a little work again. Don't worry, this won't be too hard. Even though there aren't any neat "one spot left" spaces left, we did just put in a brown. Maybe that will help us put another in.

Rad cool, we've got one! Now we're completely done with browns, too. This also gives us just two squares left in column H, so let's look at those too. We need yellow and blue to finish it off.

So we know exactly where to put the missing squares in that column. And since that also puts a blue in row 5, and we already have 4's placed, let's check out row 6.

Excellent.
There are a lot of places we can move from there, but me personally, I am going up column C since that's where we just played. We still need a red, green and purple. Well, I can't place green and purple yet, but red is possible!

A second red in 456 is going to tell us where the last red of the puzzle goes, too.

My line kinda smudged the square, but you see it, yes? Row 6 only allows us one spot.
The red there means that column G only has two spots left to fill. Gray could go in either place, but purple can only go in row 5 - see, row 4 has purple already.

Almost done! You are getting it! YOU CAN DO IT.
Row 4 has a pair of holes; yellow and green. Yellow is obvious, which makes green obvious. Same old, same old.

Let's go to column C next, because this is my write up and that's where I feel like going (you're not my real mom, so you can't make me go somewhere else, sorry to say).
C is missing green and purple. Or it was, before I looked twice.

We can certainly finish off the red cube now, since it's only missing one square. Tuck that little green away and take a look around.
5 across needs black and gray. Easy as pie; gray can't go here.

... so it goes in the other open 5 spot. And then black goes in the last space in 5 across.
This leaves us just with two open spaces in the entire puzzle.

The green cube is missing purple; so is column B. Fill that in, and you just have to fill in the loneliest black square ever in the white, center cube.

DONE. Complete and total sudoku victory.
Hopefully I did a decent enough job of explaining why I moved where I did, and how I knew not to move, that everyone who skipped this round can go ahead and try the new round that just went up. ;A;b