A couple of things help me. One is spending as much time as possible outdoors.
Another thing that’s helped me is just not giving in. I can’t always choose how I feel, but I CAN control how I act, and there are numerous studies out there demonstrating that even an exercise that forces the face into a using the muscles that we use to smile makes people feel happier. So by refusing to indulge and feed my moods, I can maintain a much more stable pattern than if I indulge them and expect others to accommodate them. I know that sounds weird in today’s “snowflake” culture, but it works for me.
Finally… rattlesnakes. 🙂 Rattlesnakes always make me feel better. You might need to find your own species, though. I suspect rattleys won’t work for everyone.