1. Give her eye-contact and see how she responds.
  2. If she gives it back to a second time talk to her.
  3. You got three seconds to approach. Don't worry about what to say. Use word association.
  4. If your at an event talk about what's going on in the environment.
  5. Don't linger on one subject. Switch topics and don't let her explain anything for too long.
  6. After about five minutes have passed give her a time constraint and ask for her number or snapchat. If she says I don't have a snapchat try facebook. She might suggest a better way of getting a hold of her. If she does this is an IOI. Add her right then and there.

I did this today and more than likely they are interested. I could have approached two other girls but I didn't want to be seen by the one I already approached.