You should look online or in your local phonebook for a program that is similar to Alcoholics Anonymous, that deals specifically with folks who are trying to quit smoking pot. It’s easier to quit, when you are working with a group of like-minded people.
Tell everyone you know (that won’t call the cops on you if they know you are/were a pot smoker) that you are trying to quit. Tell them to please not smoke in front of you, and not to try to get you to start smoking again. Tell them, that if you have to, you will have to stop hanging around with them, because being around active pot smokers is likely to make you want to start smoking again.
You should also make an immediate appointment to get a check up with your primary care physician. Let him/her know that you have made this choice to quit smoking pot. He/she may not have ever known that you were a pot smoker, but that is something that your doctor should always know about. If you keep important health information from your doctor, then he/she cannot be as effective. The doctor should do some type of base-line lung/heart check to see where you stand. Ask the doctor if they have any recommendations for you, to help you to quit and stay off of the marijuana.
Start looking into new activities that you will do, instead of smoking pot. The urges to smoke will come, and you never know when they will come. So it’s a good idea for you to have a bunch of alternative activies to participate in when they do come. Most of these activities should involve physical activity. Walking, biking, swimming, weight training etc. You should also find some mentally rewarding activities/hobbies that will give you pleasure down the line. Photography, painting, camping, ceramics, cooking. You should also look into finding some worthwile activities in which you can help other people. Volunteering for a soup kitchen, working at an animal shelter, cleaning up waterways in your county. When you are busy, have a purpose and are doing things that you enjoy, you are less likely to want or need to smoke.
You should also look for activities and groups that are not likely to appreciate/condone pot smoking. You will probably be amazed at the number of people who don’t smoke pot. Altough, I understand that there are plenty of people who do smoke pot, and most of them are probably nice people, I myself prefer not to be around people that do smoke pot. It makes me un-comfortable because I am very health conscious, try to be industrious and I don’t care for the illegal aspect of it either. Find groups of people that are like that and you will be less likely to be tempted to smoke.
Good luck to you : )