DO not try this unless the guitar you are using is one you dont care much about. Dont do this to your main guitar, or one that has alot of value. Save that for the pros. This will explain some basics to customizing the body of your guitar, by yourself. You need to be able to paint, in whatever way you want to do it. Some use spraypaint, and some use brushes. I think the best approach is the AirBrush that they use to paint tshirts with.
My own take and pattern off of angelichigo's wonderful, adorable Sleeper Boots!!