This trophy is best worked on in conjunction with the "Crime Doesn't Pay" trophy as you can work on 2 trophies at one time. Going this route, I found making a separate save (as I was on my "good" playthrough) and just heading into a larger town and pickpocketing everyone netted this trophy in a little over 10 minutes. Didenhill was a good option for me as most people had something to pickpocket but most larger towns are a safe bet.