Something I do is pin down in my head what is causing the panic. Then I pick someone I know pretty well and as myself if the circumstances would make them panic. If not, why? Try to imagine what they would say if you asked them why they're not more upset. It may seem odd but for me it's a very reliable strategy. Other things I do include opening a window and sitting by it or I'll go for a walk and focus on what I see, hear and smell. Analyzing basic things that tend to lose focus during panic can be surprisingly helpful but most importantly it's a mental distraction. I hope maybe some of this is helpful to you.

It helps me during one to elevate my feet on the wall or something else. Also, putting an ice pack on my chest, i feel like it forces me to focus on the cold sensation. Hope this helps!