There are two broad sweeping categories of spray ups that a boat can be composed of.
Any color can be done one of two ways. It can either be a solid color, or a glitter (metal flake) color.
Typically a boat is a combination of either 2 flake colors fading into each other or a combination that includes a fade into a surrounding background color.
An understanding of how a boat's gel coat graphics is achieved will help you conceive of how you would like your boat done.