Using Brushes in Photoshop

[marylee]

So I have some alphabet brushes I've been using on some of my layouts. I recently thought of taking these brushes to the next level and I am trying to make them look a little more realistic (like a rubber stamp with ink) on my pages (such as having imperfections in the opacity of the ink, differences when going over two different materials, etc.)

Do any of you know where there are any good tutorials on making my brushes look more like a rubber stamp?

I'm not sure if I explained myself well, but hopefully you get the idea.