A great resolution for the new year, in case you are late and wonder how to jump on the bandwagon, is to give up on your phone.
Not completely, not immediately.
Start with one hour. Leave it off, in another room. Or even better, check your weekly usage report and start with those apps that you feel are wasting the most of your time. Get rid of them, hide them, lock them.
If you manage to do it consistently for a few days in a row, it will stick, I promise.
The reward is now.