I've been using mindfulness for a long time. I have schizoaffective disorder bipolar type, and an anxiety and panic disorder. My thoughts used to be kind of "out of control" as in they would come so fast and rapidly and be constant ruminations over my anxieties and stuff I was worried or stressed about. Now I meditate regularly, do yoga and other exercises (I find exercise helps me feel calm afterward and have less upsetting thoughts, something about the endorphins I guess) I also journal a lot.

I find regular daily activities to work mindfulness into too like doing the dishes mindfully, eating mindfully. Focusing fully on the present moment,

Then there's a common meditation where you let your thoughts come then let them pass, you don't hold onto them, just keep letting them come, acknowledging them then letting them go which I've found helpful

Basically what I'm trying to say is mindfulness and meditation has helped me a lot