It's important to remember that, due to multi-factoral complexities, people's smoking addictions are hugely individual. What works for one person will be wrong for another. Other people will offer anecdotal advice from their quit experience. Some of it will be relevant to you and some not-so.
It's really useful if you're able to objectively reflect on your addiction and identify the problems you may have once you've quit, then plan for how to deal with them when they arise.
Withdrawal symptoms are what will drive you to lapse in the early stages of abstinence. Physiological nicotine addiction is very real, despite what some people here have suggested. Some quitters have relatively few withdrawal symptoms, others really suffer without some kind of pharmacotherapy. I normally prescribe for a duration of 8-12 weeks, but have continued prescriptions for several months in some cases.
Dealing with that allows you to be able to focus on coping with the psychological components of addiction:
Behavioural
Habitual
Social
It's worth considering that tobacco companies rely on this addiction to make money – the sole purpose of a cigarette – and will do anything to manipulate people to continue smoking, including adding particularly harmful chemicals to tobacco in order to increase it's addictive qualities (NB: this applies to all tobacco products, not just tailor-made cigarettes). It's their intention to make it as difficult as possible for you to quit.