In this entry I'll cover how to create a texture based on the unwrapped UV map. In this case, I wanted to create the waffle cone volcano in a game I was making. In some cases it makes more sense to attempt to paint directly in the viewfinder. For that see my other entry: Texture Painting. In this case with a specific uv unwrapping in mind, I wanted to modify the mapped texture.
The first step is to unwrap the UVs on the object. Then with a new empty image created, Bake the current material into that image. Render Tab > Bake panel > Bake button (shown below).
The result shown below creates an image that gives you a mapping of how the geometry is laid out. In this case, the way I unwrapped it put the top of the volcano at the top-left of the image, and the base at the bottom-right.
This made it easy for me to create a painted texture that put chocolate in the areas I desired.
This new texture could now be used on the same UV map to produce the final texture.