Congrats to everyone who has quit or has made the decision (or even the consideration) to quit. While I have never smoked my career exists in the world of substance abuse and every day I see just how difficult giving up a drug is- whether it be nicotine, alcohol, or heroin.
I am a licensed pharmD (Doctor of Pharmacy) working on my 2 year clinical psych residency with an interest in addiction medicine. Over the past 4 years I've worked in hospitals, rehabs, research labs and face to face with hundreds, if not thousands of addicts of all sorts. While my focus is typically is on people with severe substance abuse disorders- alcohol, heroin, cocaine, meth, etc, smoking is usually treated as a secondary addiction. The (unfortunate) fact is most addicts won't give up their primary drug and smoking at the same time.
No matter what the substance, the basic psychology and ultimate biological processing are the same, generally with varying intensity depending on the substance which results in how addictive the drug is (broadly speaking).
One thing I have personally observed and every successful substance abuser has told me is that you have to want to quit. You can't do it because your wife wants you to stop or you're having negative health effects. You have to innately *feel* and be motivated in your heart that you want to stop. You're quitting for the betterment as you as a whole- emotionally, physically, and spiritually. Consideration of consequences definitely helps, but you have to internalize them.
My other quick notes
1) Try as many treatment methods at a time within reason. A lot of people quitting focus on one treatment method at a time aka just hypnotism, just exercise, just nicotine replacement, just cold turkey. Why put all your eggs in one basket? Use as many compatible tools as possible within reason, even if they don't sound appealing.
2) Be prepared for the social impact quitting may have on you. Most people don't anticipate or underestimate the effect of this. It's remarkable how many relapses are caused by changes in social dynamics.
3) If you're going to use nicotine replacement (patches, gum, lozenges, etc) talk to a doctor or pharmacist to optimize your treatment. There is no shame in getting help, whether that be from professionals or medicine. Pharmacists advice is free and nothing makes them happier than getting out from behind the computer and helping people 1 on 1

4) Have a plan to follow if you relapse. You don't want to ruin all the progress you have made. Relapses happen but if you give up, then you'll never quit. On average it takes 7-8
serious attempts to quit smoking. So keep on trying.
(This is not intended as individualized medical advice. Speak with your doctor or pharmacist about quitting)