Yarn (or Color) Dominance refers to the tendency of one color to stand out more in two-color stranded knitting. It’s important to make sure that you’re always stranding your colors in the same way throughout a piece, because switching the dominant color will change the way your colorwork looks.

In this sample piece, I held the orange yarn dominant on the right side and the green yarn dominant on the left. If you look closely, you can see that the orange crosses stand out more on the right side of the work

Generally it is best to determine a "background" color and a "contrast" color, and make sure that the contrast color is made dominant by stranding it beneath the background color. The best way to ensure this is different depending on the technique you use for holding the yarn.

If you are working with one yarn in each hand, this can be accomplished easily by always working the dominant color Continental and the background color English:

If you are working with both yarns held Continental, the dominant color should be held (counter-intuitively) “on top”, or closest to your fingertip:

If you are working with both yarns held English, make sure to always cross the background color over top of the dominant color: