Habits
discipline[1] willpower pedia[2]
Atomic Habits book recommends focusing on systems instead of goals and building automatic, low mental effort, habits to improve your life. At the same time habits like smartphone 'addiction' wreck productivity.
Self tracking helps habit forming by identifying rewards of habit and what triggers current habit. It can also be used to encourage streaks and consistency.
books and communities
https://old.reddit.com/r/productivity/wiki/index about motivation and habits
tinyhabits.com
charlesduhigg.com
Gamification[3]
At least one way to build habits or at least reduce reliance on willpower is Gamification. This concept has been kind of popular lately especially with smart band and watch manufacturers. Exist apps[4][5] that can be customized to apply gamification to any self improvement effort. See also Serious Games[6].