The first thing you need to do is to establish beyond any reasonable doubt that you are, in fact, a nicotine addict.
You may feel uncomfortable with this idea - most people do not like to think of themselves as any kind of addict because the word ‘addict’ is commonly associated with images of drugs, junkies, squalor and all sorts of seediness. More importantly for our purposes, addiction of any sort is generally (and wrongly) regarded as a weakness.
Some people think that to admit to addiction is an admission of personal inadequacy, and there are also (believe it or not) some individuals who think that addiction of any sort is a moral failure, and that in general, addicts are ‘bad’ people!
Let’s get this clear. There is nothing morally wrong with being addicted to nicotine. Or anything else for that matter. Nor is addiction a ‘weakness’. Those who try to perpetuate these attitudes are not being realistic about 
the whole realm of addiction within our society today. Addiction of all kinds is rampant and the vast majority of individuals are addicted to one substance / behaviour or another. Take nicotine for example, roughly 30 percent of the adult population in most western countries  are addicted to it. If you then add the number of people addicted to caffeine in tea, coffee, cola drinks and chocolate, and further add the number of people addicted to alcohol and street or prescription drugs, then you are looking at a populace with a minority of non addicts. This is especially true if you include all the other mostly unseen addictions
such as exercise, sex, work or computer games. The point being is that to admit to being an nicotine addict is simply to identify your addiction as nicotine, as opposed to any of these other addictions. There is no shame or weakness in being addicted to nicotine and admission as such is just a recognition of the facts.
One of the psychological ‘defences’ that goes hand in hand with all addictions is the process of denial.
 IF YOU ARE A NICOTINE ADDICT (and if you are a regular smoker you almost certainly are) THEN YOU WILL BE AFFECTED BY THE PROCESS OF DENIAL.
 There are no words that can adequately express the importance of that last statement. In fact it is so important to understand that I am going to say it again:
IF YOU ARE A NICOTINE ADDICT THEN YOU WILL BE AFFECTED BY
THE PROCESS OF DENIAL!

What is denial?

Denial is the method adopted by your unconscious mind to keep you feeding nicotine to your body.
The easiest way to understand why on earth your own mind is attempting to get you to poison yourself with nicotine, is to think of it in these terms:

One of the functions of your unconscious mind is to ensure that you go through life feeling as little discomfort as possible, irrespective of how it manages to achieve this. Unfortunately, your unconscious mind does not make value judgements. It doesn’t, for instance, say to itself “Mmm.., I’ve stopped smoking and I’m starting to feel uncomfortable, I would like a smoke, but I don’t want to risk cancer so I will just tolerate the
withdrawal symptoms until they go away.” If your unconscious was able to make value judgements of this kind - ie., I won’t do (a) because it will result in (b), then no one would have any real difficulty in giving up. When this situation arises, i.e., when you start to feel the symptoms of nicotine withdrawal, this is what you can expect from the treacherous little ‘voice’ that is your unconscious:
Firstly, your unconscious will notice your discomfort. It will then compare your feelings of discomfort to the memory bank of feelings stored in your mind, and will decide on what it believes to be the source of your discomfort. In no time at all it will figure out that the last time you felt these negative feelings you were able to relieve them by having a cigarette. Having found the simple solution to your problems, it will send a message to your conscious mind. That message is likely to be “Have a smoke”. The problem now lies with the conflict that arises between your conscious and unconscious mind. By the time you get to the stage of feeling withdrawal, you have already consciously made the decision that you are never going to smoke again. This is when the real battle begins. Before we look at this whole battle process, let me tell you some more about this destructive unconscious ‘voice’. This ‘voice’ is generally stronger and more determined than your conscious mind - a lot
stronger and a lot more determined. For this reason  when  you first hear this ‘voice’ telling you to smoke, you will need to immediately be on your guard. Here’s why -
When you first stop smoking your conscious mind will start of with a high level of motivation to carry through your resolve not to smoke. Now, all would be well if your little ‘voice’ was to agree with your decision 
to stop, and think: “Fair enough, I’ll just not smoke.”  However, let me assure you that is never, ever, going to happen. Like a spoilt brat, this little ‘voice’ will then resort to all sorts of mental trickery in order that you
feed it the nicotine that it so desperately wants. In fact, it will resort to levels of deception so low and cunning, that at first you will hardly believe it possible. Here is a typical conscious / unconscious
dialogue:
U: = Unconscious
C: = Conscious

C: “Oh, oh, I am starting to feel cravings”
U: “I’ll have a smoke”
C: “No I have stopped, I must be strong”

(Your unconscious may then wait until the craving becomes
a bit stronger then:)
                                                             
U: “I’ll have a smoke now, I can stop again tomorrow.”

C: “No, I mustn’t, I haven’t really given it a           
    proper go.”
(Your unconscious might then wait until you are a bit    
 more vulnerable, say a few hours later when you have    
 just had a cup of tea and you are really gasping for a  
 smoke, then:)

U: “I’ll just have this one cigarette with my tea, I     
    never really had a proper ‘last’ cigarette.”

Some people may relapse at this stage and will decide to smoke. For those with stronger resolve the conversation may continue along these lines:
C: “No, I will try to stick it out a bit longer.”

(Your unconscious may wait until you are more vulnerable, say maybe two days later when perhaps the cravings feel quite intense)

U: “Huh, they told me that this would get easier but it’s  getting harder; sod the lot of them, I am going to have a smoke.”  
                                                           
C: “No, wait a minute, I really do have to give it my best shot, I’ll get through this bad patch soon enough.”

(Your unconscious may then do one of several things. For instance it may allow you to feel almost no negative  feelings for a couple of days and then when you are feeling good about how strong you have been and how easy’ it has been, feed you with this almost classic line:)

U: “See, I knew that I could give up smoking easily, in fact it was so easy I am pretty sure I could have a smoke now and stop again with no bother. Yeah, I think I’ll celebrate with a final cigarette.”
(You would be shocked by the number of people who have been suckered by that line!)

If, by this stage, you still have not succumbed to the little ‘voice’ then it will simply become even more devious. Remember, the sole purpose in life of this little ‘voice’ is to get you to smoke and it has no qualms about how it achieves this goal.                                                        
The next trick up its sleeve will probably be to convince your conscious mind that the pain of withdrawal is actually much worse than it really is. (You will be looking at this pain issue in some depth in the next section.) Your unconscious will also try to confuse you by allowing the feelings of both tiredness and hunger to masquerade as withdrawal:

U: (After a long and tiring day) “I’m absolutely exhausted and I’m gasping, I’m going to have a smoke, I’ll stop again at the beginning of the month when my work schedule isn’t as hectic.”

Again, many people will drop out at this (or a similar) point.