Here are my coping strategies, in no particular order:
Get away from crowds and people. If I'm in a city, I need to head for a park or out of the city if possible. Cities by their natures have too many inputs. "Normal" people eventually treat the inputs like white noise, but my wife likes to say I have the senses of a hunting dog. I hear and smell everything. In Minneapolis, we'd head for the Landscape Arboretum. It is south of the city about 45 minutes. Sometimes there are a lot of people, but the park is large enough to avoid any crowds.
Now that we live in a rural county, I like to sit on our front porch in the evening. It is quiet and relaxing, especially on clear nights when you can see the stars.
Listen to music. Classical, new age, some "Big Band" era, and soft jazz all help me relax. I also will dig out my clarinet or sit at the keyboard and play (badly) to relax. Music lets me focus on the notes, instead of the world around me. I love patterns, and music is all about following the patterns and rules.
Sit somewhere dimly lit and read. The loss of libraries and bookstores will pose a problem, someday soon. I like to sit and read in quiet spaces when I am stressed. Books are great friends and companions when I'm stressed.
Bake cookies. Yes, cookies reduce stress. How can you eat a warm chocolate chip cookie with milk and be stressed? I love baking because there are so many things to try. We have a lot of books with cookie recipes. When we try something new and it works, we make a note in the cookbook and my wife adds it to our database. When I'm really stressed, I stick to recipes we know work well.
Soak in a warm bath. Sitting in warm water is soothing, especially if my muscles ache. I don't like to soak too long, because the "prune" effect bothers me, but a few minutes can help me regroup. Plus, you feel cleaner and that's a nice thing.
Sit with my cats. Purring cats help reduce stress, unless they are the stress.