I gave up smoking 20 years ago. The one thing that helped was that I moved for work which means I had no smoker friends to party with. I picked up on my swimming and running to pass the time. Luckily the exercise and lack of company to smoke made quitting relatively painless for me. At the time of quitting I had probably smoked for around 8 years and had a 1 pack/day habit of Marlboro reds.

I agree with the parent comment. I took it one at a time and in about a month felt no compulsion to smoke.