Choosing colours can seem daunting at first but there are some simple rules in colour theory to help you out.

Firstly, study the colour wheel. You can pick one up at your local art supply store.

Primary colours (P) are Yellow, Red
and Blue. They cannot be mixed from any other colours.

Secondary colours (S) are Orange, Green and Purple. These are made when two primary colours are mixed together.

Tertiary colours (T) are made when you mix one primary and one secondary colour together for example if you mix Yellow and Green together you get a yellow green.