Been using this successfully for a couple of weeks now, if your in a club,bar, street etc it works the same.
If you see a girl/girls having there picture taken offer to take it for them so they can all get in the picture/arnt just stretching there arm out to take the group picture.
When they give you the camera cheekily turn it around and take one of yourself, then with a cheeky smile go to hand it back, then as they are taking it back tell them you are just kidding and go to take the original photo. You have just established you are cheeky and funny, roll with it from there.

The other day I did that to a girl and she said she was going to keep my picture, I told her I'd add her on Facebook as I wanted to be tagged in it, now I have her phone number and am going to sort out a date

The old picture opener works like a charm. Good job!

Didnt think it was original but hasn't seen it being mentioned so thought I'd share it