The color watch (usually referred to as the color wheel) is a great tool to use when you paint.
Here are the colors by the numbers on the clock: 12/lemon yellow, 1/yellow green, 2/green, 3/blue green, 4/blue (I use thalo blue), 5/blue violet., 6/violet, 7/red violet, 8/red(I use permanent rose, 9/ red orange (I love scarlet lake), 10/orange, 11/ yellow orange ( I use new gamboge).
I did this quick painting of (what else?) the view from my kitchen of the flowers that are blooming. The reason I chose the lavender plant and the yellow rose to paint is to illustrate how to use complementary colors or colors in opposite position on the color watch. Complementary colors when placed side by side are supposed to make each other appear more vibrant. Complementary colors when mixed together neutralize or dull each other. If you use just a touch of the complement, you get a slight dullness to your color, but if you use equal amounts of each complement, they really neutralize and become dull. If your colors get muddy, check and see if you are mixing complements together. Sometimes though you really want a neutral color so now you know how to get it. Look at the brownish trees in the background and the brown of the grass beneath the flowers, that brownish color was made by mixing the yellow and the violet colors together.