I smoked cigarettes for about 10 years. I worked myself up to about a pack a day for most of them. I have managed to not smoke them yet this year though. This is the longest I have ever gone since I first started.
I recommend quitting cold turkey. I think it is the method with the most success.
This time I made a bet with a roommate that also smoked. We bet 50 dollars to whoever could go the longest. If we make it a year then we consider that a win for both of us and the bet is off. It has worked so far! I recommend making your quit have some money behind it. For whatever reason that seems to have helped me.
Practice! I don't think people realize that quitting smoking, for me at least, is a skill that I had to get better at. I have tried to quit hundreds of times. All of those times gave me different ideas and a better understanding of how to commit to the decision.
A mantra! I noticed that the times I have been most successful, I used a mantra. This time it has been, "No Nicotine in Seventeen" Over and over. It has a nice ring to it and I can say it in my head over and over in different patterns which makes it easy to remember the decision that I made.
Exercise! It will make you feel better about yourself. I joined a soccer team and it helped me to realize what I was doing to my body. It was a weekly reminder of how crappy my lungs had become. Also if you are exercising before you quit and after it helps you see how much healthier you are becoming. This helps to fuel motivation to stay off the stuff.
I also looked at one of those charts that tells you the effects on your body. I found it useful to imagine the healing process that my lungs and heart are going through.
Go into Nature! It will relieve stress and can help distract you from cravings. Also there are no gas stations to buy more cigarettes in the middle of the woods. Here's a picture of some flowers I found to get you started. 
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I hope that by sharing this it helps at least one person. Good luck to anyone trying to quit smoking!