Since the mail man piece was just for fun I didn't go though an elaborate design and planning process. I started with a sketch and put some quick quick value on it but then decided it was lame. It's sorta what i get for just going for it, but sometimes it's fun just to shoot from the hip :)
So I reposed him and drew up a new sketch. I gave him just enough shameless value to throw some color on him. I usually like to play with a mixture gradient map tools and straight up brush work, depending, just to plan out his color palette with a few ideas about his final value.
And from there its the render factory and adjusting as I go!