this will be difficult because you haven't started viewing Marijuana in a negative light yet so I suggest you make a list of all the ways in which marijuana has done you harm, directly or indirectly. And then maybe you can make a list of things you enjoy doing without being high...and try and do more of those things.

I have been a heavy drug user for over 7 years and although I still smoke marijuana but have managed to quit everything else, even alcohol so trust me I know how difficult it can be.

Best of luck bruv