First things first: always remember to keep your eyes where they should be. Your hands, too!
When you flirt, you show sexual attraction to someone, many times playfully rather than with serious intentions. But then, who says you can’t make your intentions serious while at it?
So far you’re not being disgusting, lewd and annoying while at it, there shouldn’t be any problem.
Here are ways to flirt without being disgusting:
She may be gorgeous or super attractive to you. However, do take note on how much you find yourself staring at her, and on where you’re staring as well.
Don’t be pushy at all. Sometimes, it isn’t about space. If she is giving you short answers, or seems to be looking for a way to escape the conversation without giving you her contact number, make a gracious exit instead of prolonging talking to her. Chances are, she will just keep feeling uncomfortable if you do.
Find someone who’s genuinely interested to get to know you better instead.
You don’t want to launch straight into this. Stay aware of how comfortable she is during the conversation. If she seems uncomfortable, it’s time to stop. The safer she feels around you, the flirtier she’ll become.
Don’t be all over the place, touching her too much, letting your hand linger on hers or any other thing that projects a lack of confidence or fidgetiness. Don't forget to keep and maintain eye contact too. Again, don’t let your eyes roam to places that will freak her out.
A calm, friendly smile will not only mentally prepare you for social interaction, it will also make the words you say clearer and make you more approachable and less threatening from the outset.