hi there, I have gone through ur problem and let me tell u ...70 out of 100 smokers want to actually quit it but fail to do so....I say this not to discourage u but rather make u realize that if u had failed earlier in quitting its not ur weakness but becos of this substance of strongest addiction known to mankind.
First step to do dat is to set a " Quit date "
that is a date after u won't ever touch a tobacco product. u can cut down gradually or stop suddenly its ur choice, but no tobacco rule has to be there after dat day.
secondly u will need help of certain medications which will replace ur need of nicotine...this may be a chewing gum or skin patch or lozenge....this will help in cutting down the craving for tobacco...but then its totally personal choice and for some ppl its not pleasant to use ...den there r other medicines which psychiatrist can prescribe so as to enable u to tide over the acute phase of withdrawal.
A lot also depends on avoiding cues and ur strength of will to quit.
Stop buying packs of cigarette and purchase sticks only on as and when basis , before ur quit date in order to decrease the amount. its better if quitting involves all substances becos if u continue others such as alcohol then u r bound to lapse pretty soon.
Majority of quitters need psychological support for long time in order to stay abstinent .. Thus psychotherapeutic or counselling is required in order to stay motivated for at least a year or two for life long results.
I hope this helps u but feel free to raise further queries.