It can be done.
You've already taken the first step - YOU WANT TO.
My sister-in-law and brother-in-law were both several pack a day smokers and they both quit cold turkey. They had health issues that sort of forced the issue, but I never ever ever thought that either one would or could quit. They've both been non-smoking for several years now.
Some sort of reward system is good. If your budget is low, give yourself a star - for whatever time frame works for you.
I remember getting stars by my name when I was in grade school. Is that still done?