Mirror work!!
I read a gem of a little spiritual book called "The Toltec Way" - a bit of an off-spin of the Four Agreements way of thinking...
So the exercise is this, do it daily:
Stand in front of a mirror. Look into your own eyes. Say, "I love you. I am sorry. Forgive me. Thank you."
It's really powerful!
The other thing is the Bible, but that can get controversial. Jesus fixed all this, ya know?