Ok... heres wat u gotta do
1) check urself make sure that u really like her and don't just want her cause all ur frends have gf's.
2) Hang out with her
3) after u know her well ask her to go out with u (if she says yes congrats
) (if she says no then suck up the pain who needs her)
4) Forgot. If you really want a shot at this girl u have to let go of ur previous gf's