Brainstorm!

- the best way that helped me: block internet or somehow get away from it whenever you don't need it. If living with a family ask to change the password so you don't know it. Many routers also let you set up specific time slots when you can access. Better yet, make it physically difficult to access, i.e. have to go to the coffeeshop or somewhere else.
- get a DNS filter or a network provider with a family filter.
- get a non-smart phone and if you don't need a laptop and tablet for work, then use only a family computer for emails etc. If you life with a family.

 

Do you live alone or with others?

Yeah, the advantage of having a filter at your network provider is that you can't change it without calling them or something.

Less secure, but also possible, I think, is setting up a DNS filter at your router instead of your own PC. You can let someone you trust set the admin password for the router, so it'll be harder to change.