Good luck. My brother has 'quit' a few times and it never lasted for more than a few months, mainly because nearly all of the people that he knows smoke. My advice would be to not be around people when they're smoking, at least not for the first month or two, and especially if your GF (or someone similar) isn't around. And make sure your friends/co-workers know that you're trying to quit, it'll give you that much more support.