Spiritually asking, what’s an effective way to quit smoking for good?

I’ve been smoking for about 3 and a half years now ever since my senior year of high school. Now I think I’m at the point where I want to quit but cigs have become such an integral part of my life that I can’t even go a few days without smoking. What are some effective ways of quitting smoking. Preferably answers from ex-smokers please, since they can level with me.