I quit cold turkey after 15 years of chain smoking... Wifey had a bun in the oven... it was NOT easy...
I avoided every situation that I associated with smokin... I didnt head out for one during my break... and I quit drinking temporarily to start (smokin & drinking used to go hand in hand... didnt do one without the other). I knew that drinking would lower my inhibitions and my resolve... so I had a no booze policy.
The biggest problem was not smoking when I was driving... I started chewing LOTS of gum... mints/halls... anything & everything to substitute that oral fixation.
Since I wasnt gonna drink, I ate a hellva alot... yeah, probably not the best thing... i gave up one bad habit for another... I figured the lesser of evils.
When I watched TV/Movies, I smoked... listened to music, I smoked... this had to change, so I ate
...popcorn, chips.. you name it I ate it.
I actually kept a pack on me at all times... that way I wouldnt go out and buy one... because the rational is that if you buy it, you smoke it... but if you have it on you, you can simply say NO for now... and do shit to distract yourself... ie. tv
Good luck man, its possible... just f'n difficult.