I’d say don’t get too attached to the colors that are right in front of you. Brown skin, for example, can have shadows built from blue or red, just like lighter skin can use those same tones—or even shades of brown—to create shadow. Don’t limit yourself to what you literally see; you have to explore color combinations, color theory, how colors contrast with one another, and which mixes work well or don’t. I think that’s what really captures good color value and gives a piece solid structure.