read this to start:
It is supposed to help you avoid pickpocketers, but this article is what taught me how to pickpocket. I'm pretty good at it myself, just from practice. I'm a good bullsh*ter, so when i mess up, i make it look like an accident, not a crime. I'm still working on the bump-and-steal (where you bump into someone and slip your hand into their pocket) and I'm still working on the rolex style watch steal. Hope this clears things up.