Here is a basic color wheel. There are many, many color schemes to choose from. Some of my favorites are:
Monochromatic: With a monochromatic color scheme. You use one color for the entire piece, changing the values (lights and darks) as needed. I love monochromatic paintings because they allow you to create a mood and a feeling that are not quite as accessible with other color schemes. I used this color scheme in "Overlooking the Spread" to create a western feeling, one of a warm afternoon, with a young man overlooking his spread.
Complementary: A complementary color scheme uses two colors that sit opposite each other on the color wheel. Violet with yellow, green with red, and blue with orange. This piece, "Globe Gilias in Vase" is dominated by the green of the flower stems and vase, offset by the vibrant red background.
Analogous: This color scheme takes a section of colors sitting next to each other on the color wheel and uses them to create a harmonious, beautiful color arrangement. For this piece, "Autumn Glow" I chose to use yellow, yellow green, green, and blue green. Utilizing this simple color scheme, I was able to capture the feeling of light filtering through autumn kissed leaves in the evening. This color scheme lends itself to a harmonious color balance very easily.
As I said earlier in this post, there are many color schemes you can choose from. I merely illustrated a few of them. When you are planning your painting, choose a color scheme that will create the mood and the feeling that you are aiming for. Monochromatic color schemes allow you to focus on the subject and their story. Complementary color schemes make paintings pop, they exaggerate differences. Analogous color schemes allow you to appreciate the colors and enjoy the effects they create.
Remember, if you want to achieve greater harmony in your paintings, choose a limited palette, pick a color scheme, and stick with it. The results will amaze you!