The color wheel above should give you a simple understanding of colors and how they relate to each other.  Primary colors; Yellow, Blue and Red. What primary means is that no other colors can be mixed to make these three colors.

Secondary colors are from a result of mixing blue and yellow to get green, yellow and red to get orange and blue plus red to get purple. The tertiary colors are a result of mixing a slight bit more of one color.

Complimentary colors are opposites; such as orange and blue and so on.

When mixing the three primary colors in equal parts you should get a brown, gray neutral color. For example; if you are drawing and coloring in a banana use purple to shade the yellow. As using green to shade red and so on, use complimentary colors.

You can mix a rich black with ultramarine blue and burnt umber.  Alizarin crimson, ultramarine blue and viridian green or payne’s gray [cool tone]. Ivory black has a warm tone where lamp black is cool in tone.  Tone means the base of color and hue is the range of color.

Mixing the complements or triad colors can make a variety of shades of grays and even browns. Equal parts of paint will give a more true color. Learn your colors and play around with all of them.