So, here you go — some basic color theory:
* High values advance, dark values recede.
The viewers eye will be drawn to the area where the darkest-dark and the lightest-light meet. So values should be considered when you want to lead your audience to a certain area of your image. That means that you will have to work out, in advance, the area that is the main focus of your piece.
* Warm colors advance, cool colors recede.
True red is the warmest tone, true blue the coolest.
Colors also create mood. Red denotes power, danger, strength, war, passion, love, anger, intensity — it is the symbolism of blood and fire. Blue denotes calm, trust, loyalty, wisdom, confidence, intelligence, faith, truth, and heaven — it is a symbolism for water and sky.
There is much more, of course, but the basic keys to remember are high values advance, dark values recede; warm colors advance, cool colors recede — those will start you in expressing your imagery through color.