You start by forgiving
i know it seems impossible but you can't begin to heal yourself until you let go of the anger because that anger and resentment you hold in your heart is only hurting you.

I used to fight and argue with my mom i would say the meanest nastiest things that i knew would cut her the deepest because just once i wanted to hurt her the way she hurts me then maybe just maybe she will see how it feels.
but the meaner i got the meaner she got and she won
every
single
time.
it got worse and worse we were literally trying to kill each other she was bigger and meaner and all i was doing was setting her off and once you set her off she doesnt stop. I would always end up crying and begging her to stop but she would keep going...
Finally, i gave up.
I forgave her.
i tried to forget
I let go of the anger
i stopped trying to win
and things got a lot better. still far from perfect but so much better than before.

The hardest part of that is being the bigger person when they are supposed to be the parent and you are supposed to be the child.