1. Forget the one liner: One liner never seem to work. The woman gets the impression that the guy is trying to flirt her. Therefore the trick here is to be unpredictable.
2. Go straight up to them: This is probably the best way to approach a woman. The best way is to be confident and go up to her with out any hesitation. If you see that she tries to avoid you than move on and do not even look back. This would make her feel somewhat neglected and she would be left thinking about you.
3. Keep trying: Even being neglected once you should keep trying. It might take time but you will get results when your confidence builds up and you start building up skills.