The way I do it is a bit unusual in the vector community, but I find that it is very precise and saves time. What I do is select the outer edge first and fill it entirely, like so [link] . Then I do the inner color on top of it, like this [link] . Every different color with have it's own path and will be colored to a different layer. The coloring is accomplished by "making the selection" with a path and brushing it in, or by using this button [link] to fill it instantly. If you don't use Photoshop, then I can't really help you.