how to stop smoking

Find the reason.
There are financial reasons. Social reasons. There is fear of disease. Or simply "I came". Importantly, however, is your personal reason, that "something" essential to you, you will say when they occur inside or outside temptations, "No thanks, I do not smoke because ... . ".
Know your enemy.
Examine your life smoke, why smoking, which are situations, people, places, objects that "need" a cigarette. Recognize your rituals, but also times when lighting a cigarette, without recognizing gesture.
Build action plan.
Find a replacement for each type of cigarette. Caution must be things / activities that you like! Write your plan and get it with a thumbtack in place / places most dear to smoking. If you try, remember what you did to resume smoking and think how you react in a similar situation.
Choose a day smoker - the day will not smoke.
Choose the period in which you think will be easier - or weekend work, on vacation or at work.
Prepare one day.
And ... try again. Perseverance is key.