Another great project to familiarize yourself with color mixing and the properties of certain colors is to create a painting with two compliments using a black and white photo as reference. In this case I painted from a B&W photo of a tea pot using Ultramarine Blue and Azo Orange. Ultramarine being on the warm side and Azo orange having some yellow in it, they created some nice warm tones. I tried to mix mostly grays and highlight with some pure color for contrast. Try it with three sets of compliments, blue/orange, purple/yellow, red/green, or any you'd like. It's fun and great watercolor practice.