What I Know Now

The primary colors are red, yellow, and blue.
Some secondary colors are orange, green, and purple.These secondary colors are created by mixing two primary colors together.
Complimentary colors are colors that are opposite primary colors on the color wheel. For example, purple is a compliment of yellow. Green is a compliment of red.

To emphasize something in a painting, you could use some of the Art Principles of Design. You could use contrast, balance, symmetry, repetition, or continuation of objects in a painting.

If I was trying to create a shadow on an object in a painting, I would use contrast. I would use the complimentary color of the object to make the shadow seen. To make a highlight I would use a lighter or darker color of the object.

I would use a cool color such as blue for the background to make the object look like it was far away.

I would plan and make different sketches of how I wanted the painting to look like.