Cross is the first step of the Fridrich method for solving the Rubik's cube.
In this step 4 edges have to be solved to their correct positions.


Take a look at the graph on the right. It shows the number of moves that you need to make to solve a white cross.
Most interesting is the fact that most of the time the cross can be solved in 6 or less moves.

Color Choice

The most often chosen side to make a cross on, by convention, is white. Most people are thus said to make a 'white cross'.

However, there are a few people that are called color-neutral. This means that they first decide which cross looks easy to make, and then they make that cross. This approach saves about 1 move in the cross stage, but it is often argued that it is not worth doing it because of slower recognition times especially in F2L stage, because the color scheme is ever-changing.

There is yet one more class of people that make dual-color crosses. They choose to do either white or yellow cross. This decreases the number of moves in cross stage, but arguably doesn't change the F2L recognition times by as much.

This issue often leads to a lot of discussion, and there is no definite consensus on what cross color(s) are best to use.

Lars Vandenbergh analyzed this issue quantitavily and the whole page can be seen here. Here are the results summarized:

Looking at the results I am personally convinced that it is best to choose one color and stick with it

Placement Choice

There is much more consensus on where you should solve your cross. Here are the variations that make at least some sense:


Below is my tutorial on advanced cross techniques

And tips for making the cross on the bottom:


Dan's Cross Explanation is a nice page describing many useful concepts about cross building, but in my opinion his 3-color rule is not too worth looking into.