1. Establish eye-contact
  2. Hold eye con-contact
  3. Smile or Wave

This works every time. I got so many good interactions from women by doing this. The secret is to be relaxed and chill while you do it. When you're right in front of a girl do it. She might just start smiling or fiddling with her hair. You never know who's going to be attracted to you. If she holds you're eye-contact during a conversation and starts smiling for no reason you hooked her. You take out the whole approach factor by doing this. It takes a lot more confidence but, you'll hardly get rejected.