I start my process making a scene on blender just the basic, one sphere and 2 lights then I save it and open on Photoshop Cs5, I usually start with a base color depend of what material you chose, add some textures with color shifting, and the main paint color, detail some things like reflection on the floor and things such as the edges of the stone and the balance color.
Really hope you like it, and watch for the next tutorials that I'll be doing, this is a start point :)
