Obsessive

I would like to know(and I think I'm not the only one) how can I make a move on a stranger... for example... I see a girl on the street... she's very good looking... no one of my friends knows her and I want to make her my girflriend(well at first I would like to talk to her because I don't like stupid ppl). I just don't know how to do this...and when I think that every day lots of beautiful girls I don't know pass by me... please try to help me. Thanks.