This is my palette, but I never use all this color at one time. I select specific colors for each painting based on a complimentary color scheme (even though this painting is actually a close-compliment scheme of yellow and blue.) First I decide my "star" color. The star for this painting is yellow, so I'll want to pick out a variety of yellows and its compliment purple. My main yellow will be Cad Yellow Medium, and main purple, Garnet Lake.
I've mixed this on a piece of glass to see the color easier. I rarely use tube earth tones since I can mix them using compliments. In this case, making a yellow ocher, which I can easily make lighter and darker, or warmer and cooler. If I use a cooler and bluer purple, the colors will end up a bit on the green side, and I'm seeing a lot of greenish-ocher color in the shadow side of the "flower."
These are the rest of the colors I will use for this painting, plus white. I love having lots of choices, so I usually add warms and cools for each compliment. For my yellow side, I add a warm of Cad Orange, then four cooler yellows. I'm not going to add a warmer purple, because I can warm up the one I have with the Cad Orange, but I am going to add several blues.
That's my color scheme theory in a nut shell.