I would suggest using the same method you used to get off the booze and drugs, it worked for me, I made my one year sober mark as the beginning of stopping smoking, I have not had a smoke in over a year and a half, I used the steps of AA to quit smoking, I know have one bad thing left, skoal pouches which I plan on stopping on my 3 year sober and 2 years not smoking mark.
It is well worth it, but I have to say that I still on occasion see some one lighting up in certain circumstances and I do have that thought pass through my head, not strong at all..... but still there.
Good luck.