Giving up cigarettes.

Good luck!
I quit for 4 months, but gave in a while ago. Now I just cut back to smoking on the weekends.

The first 3 or 4 days are the worst because you gotta cut the habit part of smoking. Like smoking when you wake up, before you go to sleep, after you just ate a meal, ect.

I would stalk up on some gum and whenever you feel the craving just pop some of that in. Also getting another hobby(like wood work or model cars) that will keep you occupied and not thinking about smoking.