I quit after getting strep throat. My doctor said I wasn't allowed to smoke. I normally don't like smoking anyway when I'm sick, but I was sick for a solid 2 weeks and could barely move, let alone get up and smoke a cigarette. By the time I was better, I hadn't had a cigarette in 2 weeks, so I just took it day by day then. I've slipped up here and there taking a puff of a cigarette, but I did so only after 7 months of not touching any nicotine. It's a day to day, moment by moment process. Now I've been smoke free for almost 3 years.
The most important thing to remember about quitting smoking is that you're not smoking RIGHT NOW. Stay in the moment about not smoking and you'll find that as you go longer, the cravings get less and less. Reward yourself with milestones.