I smoked for 24 years. I quit last June, a few months after my first kid was born. Being a new Dad at 42, I figured that I better take care of myself if I wanted to see him graduate. If I am going to die young, I would prefer it be in a blaze of glory, doing something I love, rather than a slow, painful, undignified wither. I used Chantix (prescription nicotine blocker), which helped, but the side effects were hell- bad dreams, insomnia, nausea if taken on an empty stomach.
Ultimately, you quit with your brain. Your desire to live longer, walk farther, smell better, and save money overcome the impulse to get a quick fix. Start by making some easy to follow rules, like no longer smoking on the can, or not smoking in the house, or your car. NO consecutive cigs. Then fight the urge when you want one, and see if you can go an extra hour before you light up, etc. Eventually, you will learn that your will is stronger than you think, and that will give you more confidence.
I think it is a good idea to have some sort of fitness program going at the same time. Anything that tests your cardiovascular endurance would do. This will give you a baseline to judge and appreciate your improvement.
Last October, after being smoke free for only a few months, I put my 10 month old son in a backpack carrier for my annual fall hike to a favorite area. The trails run up and down a bluff that follows the Missouri River. In the past, I have been winded on the uphills. Last fall, I noticed a HUGE improvement, never really getting winded on the uphills. Although, my legs and ass were burning due to the extra 35 pounds of kiddo and gear on my back.
Good luck! Keep trying