The foundation of self-control is self-knowledge.
The moment when you acknowledge you have lost your self-control.
How to train it?
Just wait 10 minutes before doing what you’re thinking of doing.
In that time your brain becomes wiser.
Give yourself 10 minutes.
Know what your impulsive self-wants, and what your wise self-wants.
Recognize when one is in control.
Instead of reacting impulsively — pause — and plan out what you actually want to do in response to that stimulus.
Resist the temptation.