1)pick a street with shops on
2)then walk down it at night time
pretty much guaranteed to find some!
to make it less obvious you are going in make sure to wait outside it for a bit suspiciously and then when you finally go in be sure to look both ways, at least 2-3 times each direction to check for people. even if there are people they will see how confident you are.
also most wowo’s and family marts (the small convinience stores) sell a few things, if purchasing from here make sure only to look both ways before paying the cashier. this way they will know you are cautious of pickpockets and make them believe you are more confident and cautious