For me, relapse always came when I started feeling good about my recovery. Started thinking that if this time I just have a pint or two, I can keep it at that. Never worked, of course.
I think now the trick for us is to never let ourselves get complacent. Never let ourselves think "ooh, I've got it nicked now, a couple won't do no harm". That's the point the cravings start, and from there its all over but the puking.