That's how I do it.
Seriously, you don't have to proceed after the supposed "finished" piece as... Sometimes, the more light/brightening/effect you add, the worse it became
I'd assume you know the basic of digital art program (Gimp or SAI). I'll try to answer your question if I'm capable to. (But not something about Photoshop. I'm not really good at it
Hope this helps anyone who's weak in background