Also are you approaching and just talking? You need to smile, move, and challenge her.
I meet so many people that can only speak in a conversation, they don't respond and they don't wait. They just want to keep on talking, like telling the same story or bringing up the same point like 20 times in the same night.
When you speak with a girl you should have a smile on your face, like a genuine smile, not a huge grin. IMagine her first thought being "look at him, why isn't he smiling" than put the smile on your face, after she sees you. Than approach since you will have eye contact. Than talk to the girl.
Don't just go up and say random things, try to get her involved.
You can start with *smile* "do you have the time?" which should be very easy. Than move on, try to make her smile right away, tell her she has nice shoes, and say "thats why I got the time from you, and not that guy". After you make her smile ask her for her name, introduce yourself, tell her you aren't from around here even if you live right next door to her.
Does any of that make sense to you right now, or would it be better if I just shut up?