Truths from the first post...confidence, humour and to some extent aloofness, really depends on the situation though. I don't generally go clubbing to meet guys, I find the sleaze factor really unappealing.
Not that you would lol, but here's an example of what NOT to do (I was in third year of Uni, for reference)...
A guy started talking to me in a club, he seemed nice and we got on well. A while later I said I'd see him around because it was my friend's birthday and I wanted to spend time with her. He asked for my number so I gave it to him (I would come to regret this). A couple of hours and many cocktails later, my friends and I were mad dancing and loving it. He comes over, asks to dance and moments later asks if he can kiss me. Considerate to ask but spoils the passion really. Anyway the night ended, said goodbye, fine.
Next day he texts me early afternoon asking what I'm doing. I text him back and then comes a barrage of about 8 texts in a row, none of which I had replied to because I was out and steadily becoming freaked out by the over-keenness/stalkerish nature of the texts. This guy was about 25, not someone younger of whom I could perhaps understand such behaviour. I'd thought he was ok the night before, but it really put me off and that was the end of it. Oh, apart from him then texting every few days for no reason at all, gah.