In my darkest days it was keeping busy, walking & exercise, appreciating nature and animals, photography, DIY, in my spare time. Keeping busy in my day job too, moving jobs for a better working environment.
Basically, keeping busy and staying active and getting out of the house as much as possible! Not allowing myself time to dwell and languish in misery. Even on the darkest days, getting myself up and on with something. Making every day count, so doing something, however small, every single day, whether it's a walk, a visit to a local nature reserve, papering a wall, washing the car, gardening, or whatever. Just "something" to get the blood flowing and the body moving.
I'd often write myself a "to do" list with the smallest of tasks on it, and gain pleasure ticking them off, to prove to me that the day was worthwhile.