Color is a subject you can study and evolve in your whole entire life. It is hard to understand and get a grip on, at least for me that is, and the only way to learn, I think is to practice, so to paint a lot, and make a lot of mistakes. Also you can become more conscious about what you are doing by writing it down. So here are some thoughts on my approach to color, things I try to focus on while westling with color and a some links to material I study to get a better understanding of color. I know color and value go hand in hand, but this is just about color itself.
One thing I try to do is to use the level of saturation in my color to guide the viewers eye. This means that the main focuspoint of my story contains the most saturated colors. Everything that is secundair for the story is less and less saturated. Simplified I pick my saturated color from the right side of the line, and my less saturated colors from the left.
Another thing I try to do is to approach the whole scene with one general color 'feel' and start painting from there. So for example in this piece I thought the oven and the girl are telling the story. They are going to consist of warm saturated colors, a yellow-orangish color. It is the focuspoint of the story. Therefore I started the painting with the complemantary color of that, a purplish colder color.
This leads to the next thing I try to be aware of while painting and that is color temperature. I think this means warm lights, cool shadows, and vice versa. And for instance using complementary colors in a dress that is, say it is green , then there can be reds in the shadow of the dress. The goal is, I think, to make your colors richer, not by adding black and white to the color, but by adding color to it, you can intensify the color.
The first book I ever read about color was Kleurenleer by Johannes Itten. This was about 10 years ago, when I was in art school. At the studio I've watched this DVD like a gazillion times, in the hope of understanding color and light a little bit more. And of course the internet can also provide you with some interesting feedback about color (and value). A really interesting video I saw recently was by artist Marco Bucci. In this video he talks painting fundamentals.
But the only way to really learn and understand is to do it yourself. So paint, make mistakes and learn from them.