hello, in such a long history of having tobacco dependence you have to stay calm and keep your self motivated.because one of the biggest factor to quit drug dependence is a will power.anyhow , there is a lot of companies having nicotine chew-gums and patches.in start when you feel very much craving take one chewgum and like this you have to tapper off.for instance, if one day you ate 5 chewgums in a next day you should decrease this number to 4 and so on.secondly take a lot of water.in start you will expriance dry cough but its alright this is a positive sign, because the normal epithelium of respiratory tract is again taking its place back.