One major purpose of the color wheel is to give artists a guide for mixing colors. If you’ve heard of “Primary Colors”, this refers to yellow, red and blue. You can think of “primary” as meaning “first”, because you can’t create these colors by mixing others.
The next group of colors is called “Secondary Colors”. If you mix any 2 primary colors together, you will get a secondary color. Secondary colors are purple (blue+red), green (blue+yellow) and orange (yellow+red).
A trained painter is able to create almost any color imaginable using only primary colors. White can be added to lighten a color (pink). Not all of us find it so easy to create from just these 3 colors, and this is where the color wheel comes in handy. By looking at the wheel, we can see that orange is placed halfway between yellow and red, meaning that yellow and red can mix to create orange. If you want a slightly lighter orange, just add some yellow and you’ll get yellow-orange.
Take a look at the following image and see that its basic colors have been separated below.
If you were planning on creating a painting based on this photo, you would need yellow, brown, black, light blue, and yellow on your palette. A detailed image such as this can be created by mixing these colors to get all of the subtleties you see within the flowers.
If you’re at a store and feeling overwhelmed by the amount of color choices, just remember that starting out with primaries, secondaries, some white and brown can be enough for a versatile palette.