I feel that eye contact is very important.
You can try to look at her more often and when she look back and
maintain an eye contact with you for a while, you smile at her. If
she response by smiling, boy u have a chance there.
If first time not comfortable to approach her, do the eye contact
thing for a few more times(not within the same day). You must
really walk up to her and introduce yourself/talk to her. If not, u
can keep smiling at her forever.
