@Birdofparadise8 I've spoken a bit about stuff I do before - like noticing my signs of dysregulation and responding with becoming aware of and controlling my breathing, and deciding whether I need to change up my situation. Taking deep breaths and taking a step back from a situation also helps me to ensure I am not just reacting, I am instead responding (i.e. with thought and consideration, not just acting on primal fight/flight instinct). Reminding myself that all emotions have a purpose, and all emotions pass eventually. Naming the emotion helps too, and seeing it for what it is trying to accomplish/what evolutionary purpose it is related to, rather than seeing it as a bad experience or a sign of weakness. I also go for a walk, have a shower, talk to a friend or call a helpline, and if the emotions are Really Big (can't stop crying, feel like punching things) then I let them be big - I have a solid cry, or I punch a pillow, but I do so only if appropriate (don't go punching stuff in Kmart lol).
Breathing is a huge one, I cannot overstate how much it helps with regulation. Noticing and focusing on the physical actions I'm taking is important to me, because emotions are a physical experience. Even if my brain is being loud and busy trying to interpret and make meaning, I try to consciously bring it all back to the feeling, the physicality of it, what it wants me to do, and whether it is rational, or just reactive, to do that action. And remembering that sometimes, I'm just gonna be a mess for a while, but it always, always passes.
I have also spoken often about how helpful I find affirmations and working on my positive self-talk. So, not shaming myself for how I'm reacting to something, talking to myself like I'm soothing a child, reminding myself that I'm not weak, stupid, needy, or any of the other nasty stuff I used to berate myself with all the time.