Here is a list of techniques that will not help you to attract women while out dancing:
1. Saying "Are you having a good time? Well, I'm not."
2. When the woman tells you she is in a relationship, picking up her left hand, pointing out that there is no ring on it and thereupon deeming her relationship pointless, and then leaning soddenly on her and telling her that if her boyfriend leaves her, you'll be there if she wants to call you. "I have a boyfriend," should not be interpreted as a challenge. Seriously. Invalidating someone's relationship also makes you remarkably unlikable remarkably quickly.
3. Literally wearing sunglasses at night.
4. If you ask a woman's name, and she tells you, and then she starts to introduce her nearby friends to you, interrupting her with "I didn't ask for your friends' names. I asked for your name." Nope, not cute. (Think about it: maybe she is not single or interested, but the several lovely women dancing with her are, or could be. You just shot yourself down, kid.)
5. Touching her butt, especially with your groin, in lieu of speech-oriented introduction. Even if she is already dancing, this is not a good way to ask her to dance with you. The fact that women do not like this type of greeting does not mean we are sexually repressed; it simply means we are not bonobo chimpanzees.
6. Tugging on her hair to get her attention. That's just weird.
And another thing: has anyone else noticed that for some reason, a nightclub is the only environment in our society where it is acceptable for a man to place his hands on a woman's hips in order to indicate that he needs to pass by her or is passing her? Or her waist? Instead of just saying "excuse me," or tapping her in a non-erogenous zone. In any other locale, the shoulder is where the "excuse me" contact is made. It's like women suddenly don't have shoulders because we've stepped into a club.
There are a lot of nice men out there who are totally respectful and polite--I often say things like "Thank you--I just really want to dance with my friends tonight," and that mostly gets across without any hard feelings in either direction. And I'm totally, and very happily, off the market anyways. I just feel the need to make the points, not so much for me (although if a stranger never pulls my hair in a club again, that will be a-ok) but for, I don't know, gender relations in general.