maybe something you need to work on is availability. standing by yourself in the open is an intimidating sort of situation for anyone to approach you, let alone a girl going against established norms (ie men approach women and women dont approach men lest they be called sluts or thought of as 'easy'. in overall terms, a girl making eye contact with you for more than .6 of a second is the equivalent of a man saying hi) so what i suggest is thinking about what you can do to make yourself available.
in a club environment, this generally means standing in a high flow area where people are likely to be shoulder to shoulder with you, so that saying 'hi' to someone can easily be taken as merely being polite (even though the ulterior motive is romance) or on the dance floor, where you can work the floor by dancing through the crowd a little so taht you are in easonable proximity to the girls you want
outside a club environment the single easiest thing for you to do is to get used to saying hi to people all over the place. men, women, fatties, shorties, uglies - everyone. hell, i even say hi to jerseyart and alien amp pharm. the reason for this is taht by coming across as friendly, people are more comfortable doing the same to you first the next time round, and also, if you only say hi to the peopel you are interested in, people see through you from 50 feet and you look like wanker. besides, its nice saying hi to everyone - you can make friends you never thought you would
anyway, not that youll take this advice, but thats not the point. maybe one day when you trip over and bang your head on the ground to come to your senses, youll realise.
sometimes being hot is a problem, and people are intimidated by you. im not saying that im the hottest guy out there, but i have lost several girls because they didnt think that id be interested. oh well.