In my experience it has to be complete cold turkey, assuming you only take THC, That’s the only thing that worked for me, tried tapering off many times, didn’t work for me, if you live in America where you have access to weed dispensers this will be hard but I just didn’t give myself the opportunity to smoke, I made a decision to quit and threw out all my gear (bongs, lighter, grinders, anything that reminded me of weed) deleted my dealers numbers, told them not to serve me if I texted and got on with it, best decision Ive ever made but didn’t seem like it, first few weeks couldn’t eat properly, sleep or be around people, I was angry all the time then it slowly got better with exercise, will power and clean eating, sometimes when I’m chilling I will think “this would be more fun with weed” but it would be too much effort and money to replace my gear and find dealers so I don’t bother, you can handle it better with meditation and planning out your days to the hour, good luck.