I have no idea if anyone is going to need this any more, but I've found a much better way than anyone has mentioned so far. Attacking the civilian is a bad idea, and the guard is only handy if you can bribe them. If a guard is near by and says 'stop!' then the fight stops. After a pick or 2 I'd stop, they seem to catch me even with 100 PP, and there's never a bribe option. Meanwhile, pickpocket every civilian, but only take things like money, lock picks or arrows, seriously.

I did this to all guards in Markarth, Whiterun, Riften, and a couple of other places. Do so at your own risk, and by period of time I mean at least a few days. Only hit each guard once, I THINK after a period of time you might be able to hit the guard again. If your caught after bribing there's no option to bribe again. I've never been caught taking back the money. When this happens, wait for 'HIDDEN' to appear and take back the money you bribed. In my experience, they all demand 420 septims (ish), except for the Riften area, where it's only 12 septims. Keep giving and taking items until your caught. Steal everything they have that's easy enough, like 90%, if your lucky enough not to get caught, re-place it on them, and anything else you stole and don't care about. Basically, you can't get away with bribing thievery unless your a local 'someone' to the guard. For me, everywhere else was fine because I've completed the Stormcloak quest first. For example, pick pocketing in Riften using this method means first joining the thieves guild. also you have to gain some king of respect that applies to the area your in. I gained 50 pick pocketing levels in half a day by doing this:

Easy 100 pickpocket skyrim