This might be an unconventional suggestion, but I am in the process of quitting smoking tobacco (not quitting marijuana though) and I have found that getting into drinking tea every day is helpful at least when I am at home. I have lighter, less-caffeinated white teas for right when I wake up, some darker oolongs and such for when I want a drink more like coffee, some herbal teas for nutrition, herbal teas for immune support, herbal teas to help getting to sleep, and some others that are just nice to drink like some chais and ginger teas. Then there's all the plants from the garden which are fun to make into teas. Because I have options as to which tea I want it's like taking healthy drugs and there's hardly a time when I don't have an appropriate tea to drink.
I have tried pills, gum, chemical inhalers, the patch, and licorice root in the past with not much result but by becoming fascinated with tea I think I have found a good mechanism to help myself not smoke.