One of my art teachers once said to me that it takes at least 10 years before one gets a bit confident about mixing and using colors. So true, even now, after 20 years of painting, I still learn new things about working with color.
Last year, I started documenting and coding my color schemes. This is useful when I want to remix a specific color afterwards.
Also, where I previously started a painting with a very complete palette of colors, I now tend to work with a few well selected colors. I discovered that I can create dynamic, visually exciting color combinations by simplifying the complex world of color.
I learned from my dearest art teacher Nancy Hillis that "there's infinite freedom and creativity within a structure or constraint". Even with only a few colors it is possible to mix endless variations.