My experience is what you do after you get up in the morning have great impact all day long. I use appdetox on phone and webblock on chrome to block easier news/SNS apps for the day and only allow them or gaming for a fixed time at night as reward(after a while I find solving hard problems more rewarding than yhose shallow entertainment). I find it became easier to focus on hard things after starting doing this. If you do easy things at morning, the whole day is ruined. Also I run or swim at 5pm.