Atheist; I packed it in several years ago without any aids other than will-power, if I hadn't I'd probably not still be around annoying you. Any way you do it it's tough.
What you have to do is think in threes; getting through 3 days, then 3 weeks, 3 months & surprisingly, 3 years (there's always a temptation to think "Now I'm cured, one wont matter").
For a while avoid the things which you associate with having a cigarette, instead of having that mid-morning coffee, drink a glass of water instead.
It's less difficult if you can share your suffering. If you have a friend who has undergone it, talk to them about it, perhaps phone them up , (they wont mind) tell them how hard it is & ask what it was like for them.
Once you get through those first 3 weeks you will start to feel so proud of yourself.
Best of luck!