I smoked for 16 years. I finally quit cold turkey in February '06. The first 3 days is the absolute WORST. You will be extremely agitated & emotional. Just plan on it. After the first week, things will begin to mellow. Have lots of chewing gum on hand. I kept a drinking straw that had been cut down to cigarette length in my pocket so that I could have something to hold & flick. I would even "draw" off the straw when things got really bad. After about 3 months, the cravings will subside a bit, but your body will begin to respond in a very positive way. You will have more energy & stamina. You will have dreams that you broke down & started smoking again. This is normal.
I don't really know how I did it. I attribute it to my stubbornness. I simply REFUSED to smoke, no matter how bad it got. Another lesson learned is that I can never, EVER, have another cigarette, not even a puff, or I will be right back where I was with that cruel,cruel monkey on my back. I don't know what your feelings are on pot, but I smoked a lot of that too. Really helped.
Now, 15 months later, I still have the occasional craving, but they are very easily controlled and usually only rear their ugly heads when I've had too much alcohol.
The thing to remember is that every day will be better & easier than the last. That only works though if you stick to your guns. Like I said, NO tobacco whatsoever.
Best of luck to you. This will likely be the hardest thing you've ever done, but you CAN do it. It just takes a tremendous amount of backbone & resolve. Your mind will be your worst enemy as it will try to trick you into making excuses that enable you. Don't reason with yourself too much. Just refuse to smoke, no matter what. Things will get better.
Sincerely,
-Breck