Analyse your habit

Before you stop, you need to analyse your habit carefully so that you know when and where you're at your weakest and you can take action to stop yourself lighting up. 

For a week, keep a record of the number of cigarettes you smoke, when you smoked them, where (as soon as you get up in the morning; when you're out with friends; on your coffee break; etc), your state of mind when you smoked, (tired, stressed, anxious, happy, drunk), how much you craved nicotine (on a scale of 1 to 10) and the enjoyment you got from smoking (on a scale of 1 to 10).
Once your week is up, analyse your habit meticulously and you'll face up to how much you smoke, when and why. 

Then you can start thinking about changing your habits to avoid your triggers and weak points and to disassociate certain things from cigarettes (eg coffee and alcohol). For exmaple, yoy might smoke for enjoyment and relaxation, socially, at work on your break, when you're bored, when you're in on your own, when you're stressed out, etc etc).