When it comes to flirting, you can get your point across very easily just using your eyes. Take a moment and watch people who are in love. See how they look at each other - they stare directly into each other's eyes for extended periods of time.

Look at mere friends. See their eyes? They seem to flit back and forth, making eye contact, but never extended eye contact.

What do I mean by extended eye contact?

Holding someone's gaze for 1-2 seconds and looking deep into their eyes during that time. I realize that couples may look at each other in this way for longer periods of time, but remember they are ALLOWED to do this - they are a couple. For our purposes, you are just flirting.

If you were to try and stare into some girl's eyes for long periods of time (especially if you don't know her), she will think that you're staring at her and she'll think that you're strange, as you're making her feel uncomfortable.

The goal here is to make eye contact with her, and to hold her attention by looking straight into her eyes for a couple of seconds so that she gets the idea that you're interested in her.

Be sure to smile, or to at least have a partial smile on your face as you do this. If you stare at her like this with a stone face, you'll freak her out.

She'll either think that you're mad at her, or that you're just some type of psycho (both are bad).

If she seems to quickly look away, she is either playing hard to get, or she doesn't have an interest in you. Either way, if you feel that she's worth the effort, you will probably have to pursue some decent conversation with her.