Change habits (good and bad) by workin on each component of the Habit Loop.
Source
The Four Laws of Behavior Change
There are 4 rules, centered around the Habit Loop, with variants for positive and negative changes:
Enabling Good Habits
Make the cue obvious. Make the craving attractive. Make the response easy. Make the reward satisfying.
Breaking Bad Habits
Make the cue invisible. Make the craving unattractive. Make the response difficult. Make the reward unsatisfying.