For me, just not having it around helps. If it's there, I'll smoke. That's an insultingly simple solution, but I tend not to be very social. I just make sure I'm not around it.

That stated, bpcyclist also mentioned AA. It's not for everyone, but it sure helps me with my alcoholism. I was a very heavy (blackout) drinker. There's no way I could have quit without AA - I sure tried!