1. Delete your accounts, if possible. Maybe not YouTube though if you rely on Google for Android or email [1].

2. Install the LeechBlock extension [2] in the browser on all your devices. Lock out the sites you want to lose from your life. You can add a time-limited override for some, if you want. Dont feel bad or weak about yourself for doing this: these sites are largely designed with psychological input to be addictive.

3. Find something else to do. If its reading, always have a book in progress and one that you'll read next. Or cooking, exercise, sex, study, whatever.

4. Exercise anyway. Hydrate, sleep well.

[1] Don't use gmail - google are not on your side. Get a domain and use a proper email service like fastmail or protonmail. Sign up for kagi and dump google search.

[2] Available for Firefox, Chrome, Edge, etc. via the browser extension stores.