Here is a pic that I did as one of my homework assignments from class. We had to basically create a number of brushes and then use all of the brushes to create a scene.
So I decided to use the layered approach, using overlays and such and a bunch of brushes to put it all together.
http://murdockink.tumblr.com/
http://murdockink.blogspot.com/
http://moebocop.deviantart.com/