I quit 33 years ago after having smoked for 10 years, so in my case, I probably wasn't as addicted as some. Furthermore, the tobacco companies like Brown & Williamson have been found adding addiction enhancers like ammonia that keep folks puffing away -- until their lips fall off or the fake larynx is implanted. Gotta love that!
All too often I hear folks who "want to want to quit." And they don't. Repeated failure after failure, it's a hallmark of those who simply don't make the decision to quit.
It boils down to making that decision. Period. If you don't make that decision, you don't quit.
I hope for your sake that you DO make that decision to quit. And follow whatever methodology that works for you. For me, I switched to a pipe (without inhaling) and when that got to be a pain in the ass because of the cleaning, tamping, relighting, packing, etc., I just threw the damn thing away and never looked back.
But fundamentally, it's the decision to quit that has to be made up front.
Undoubtedly franksolich will weigh in as I believe he might be the most recent CC-er to have quit.