Color theory paralysis is real. I spent two years reading books and watching videos about color and my paintings didn't get better because I was learning about color instead of using color.

The single rule that unstuck me: commit to a dominant color temperature and make everything else serve it. If your light is warm, your shadows are cool. If your light is cool (overcast, indoor fluorescent), your shadows warm up toward earth tones. Violate this rule intentionally and deliberately, not accidentally.

After I internalized this rule, every other color decision became easier. I stopped asking 'what color is this?' and started asking 'is this warm or cool relative to my dominant light?' The answer told me most of what I needed.

The second rule: reduce your palette. If you're mixing from more than five base colors you're probably fighting yourself. Master a limited palette and your color harmony improves automatically because the colors share base pigments.