Cool ass trick my friend taught me to subtlety see if a girl in close proximity is eyeing you. It's simple, just yawn. Psychologist have found the reason it's contagious is because of some deep rooted empathy we have for one another. Anyway's it's stealthy because you can look away, yawn, give it a few seconds and then check to see. Once could be a coincidence, twice maybe..but if you utilize this at a party or some social setting throughout the night, you should be able to gauge how often she's checking you out. The only downside I can see is that she'll probably think you're rather tired.