First,
Download this. subliminal message program for your computer.
Subliminal messages | Mind of a Winner
It will feed you thousands positive affirmations to subconscious mind everyday while you bullshyt on the coli. These messages will be flashing so fast you won't pick up on them but your subconscious mind will.
Second,
Breathing. You got to learn to control your breathing to quiet the mind. I personally use triangle breathing.
Third,
You have to question negative self talk. Every time you have a negative thought, question that shyt. I came to the realization that i'd programmed myself to think negatively, you have to stop the thought and become solution minded.