When I was homeless I use to pick easy pockets and grab bags/purses. I'd never assault anyone, only stealing opportunistically. If they put their purse/bag down while having coffee or whatever.

My tactic was to idle across the street from the ATMs during busy weekends and wait for the right person. Typically loose fitting pants, wallet in the back right pocket (easier as I'm a righty) and either with a large wallet or loose pockets. Then I'd simply tail them and scope out their pocket, if I felt it was a go-er, I'd keep with them until they got to an intersection, an escalator or a lift. I'd then, very carefully try pinch the top of the wallet, and as they walk forward, I pull it up. They never feel it leave their pocket.

But purses and bags are easier. Women are frequently careless and put them down all the time. They were good targets, I'd hover around the general meeting spot in my city and look for 'rich girls' waiting for friends.

Then I'd tail them (rich girls have a lot of cash on hand typically) and wait for an opportunity.

The hard part of grabbing bags is the run. You need to beat it and take a corner quickly. You also need to be very aware of any brave souls who'll try to tackle you.

With wallets and purses you can bin them when you break LOS from your mark and then circle back around and collect it after you lose them. Failing that, you need to ditch it somewhere retrievable and out of sight, so dumpsters in alleys work well.

If you get caught then, you have nothing on you and it's their word against yours.

It's very hard to convict pickpockets because if they don't have the stolen object on them at the time and there is no CCTV around, then there's no arrest.