Mantras
Short and to the point
Some people find recovery mantras extremely effective.
Many of our negative thoughts (e.g. "I'm not good enough") are well-worn patterns, deep grooves for our brains to easily slide into.
It can take a lot of work to wrestle with the thought and reframe it more positively. If I've got a particular sticky thought that's proving hard to reframe and move past, I like to pull out a mantra.
Short, easy to repeat, the point and only the point.
"Breathe."
"I am enough."
"I've survived 100% of my worst days so far."
If it feels corny, pick something else. And next time your brain won't shut up, try yelling back.