Make eye contact with a girl and hold it until she breaks first. DON’T BREAK EYE CONTACT FIRST. If she digs your vibe or look, she will think, “Hmmm what was that about,” and be intrigued. Some time later – before some other guy starts humping her leg – make eye contact again. If she holds it for longer than a second, she is open to the possibility of having sex with you, and will be receptive if you go up to her and say hi. This is like a pre-approach filter, so you don’t waste your energy talking to girls who probably won’t be into you. Don’t even bother making eye contact with girls – or anyone – if your appearance is grossly unpleasant to the eye.