If you want my advice: if something isn't working for you, change it. People wouldn't hesitate to take this attitude to most things in life - why not apply such thinking to your lifestyle? Of course there is something to be said for being oneself, but if you're not attracting guys maybe there is something putting them off which you could work on?
So for example, don't be too nice. It works even better in reverse, but if a girl is a bit mean to a guy (in a semi-joking manner) then it'll probably make him want you more. A girl I have no interest in called me a nerd the other day and for the first time I took notice of her "like that". Might just be me, but I think it might be a more general thing. Don't be too friendly or you'll be friends. Be fun, be exciting, be different, be original, be different, be a challenge.
There you go - some semi-drunken ramblings!