Deep breathing and visualization work well together to calm your heart when it's beating too hard, to lower your cortisol levels, and to get your anxiety down to manageable levels.
But what a lot of people think is they just do it like three times a week or something, and I'm sure that helps, but what is better is to do it every night, and then also, when you're panicking, meditate.
Use those guided meditation relaxation streams on your music provider of choice or even YouTube. I hope you fall asleep easier every night and prepare you for when you need to instantly go into meditation because something incredibly stressful is happening right now.