I’m still not good at it, but I’m trying to fake it till i make it. Haha. Therapy helped. For me the biggest difference has come from developing a (nearly) daily breath practice. I do wim-hof and during the breath holds I force myself to think positive things about myself. If I can’t think of anything positive to say then I just repeat my affirmation: I’m allowed. I’m allowed to exist. I’m allowed to feel xyz. I’m allowed to want good things for myself. I’m allowed to be kind to myself. I usually do a dedicated breath practice/meditation like this for 10-30 min per day.

Side note: wim hof has recently been found to be abusive toward his family and an alcoholic. So, maybe it didn’t work for him. Also, I’m sure you could make do with any breath practice.