Really assessing the cost of quitting and being honest with yourself about how much you want it.
This helps to do on the front side of dealing with some types of addiction or bad habits, in my opinion.
Are you willing to endure pain to quit?
Are you willing to be really bored? Are you willing to miss out?
Do you want to quit badly enough to face embarrassment?
One possible pathway forward is to tell people who love you about the addiction—specifically I'm thinking of people that you really don't want to tell. People that you respect. Tell them you're going to quit and that you wonder if you can update them on your progress with it every few days. Willingness to endure pain and embarrassment required!
Or you could take it a step further, find some app or something that blocks Youtube (or whatever site you want to quit), install it, and set it up so it can't be deleted or uninstalled and have a friend or loved one set the password. Again, you've really gotta want it bad to go to extremes like this, because it will definitely involve discomfort on your end.