Here's an idea. She would be sitting somewhere chatting up with some of her friends; make sure that all of them are girls. You go sit somewhere nearby pretending to keep yourself busy by reading a book or smoking a cigarette. At the same time listen to their conversations. If you feel the gist of what they are talking about and have an opinion to share about the topic, interject them. They might be surprised at first, but if they enjoyed your feedback, a conversation flow will occur. Try to maintain the talk about non-personal things. The topic of the conversation could transition from politics to the latest hollywood flick. At that time, neither you nor her know each others name. Do that as soon as you plan to leave, saying "By the way what's your name?". Not only will she gladly give it to you but she will also eagerly ask for yours. Next time you see her, you can easily approach her and maybe take it to the personal level; ideally if she is alone at the time.