Take vitamin D3 with K2 (basically everyone is low, and the k2 massively increased absorption), try to get out and get at least some outdoor time ideally with sunlight (even if you're covered up, the fresh air will do you good), try to set aside time for part of the day to explicitly avoid a screen. Something like yoga would be great, exercise in general, but yoga gets those good stretches to get the lymph moving

Eat well, sleep well, exercise - you know, all the stuff you already know but could always improve on. Do extra self care and make time to socialize

Maybe see someone to get on a SPARI/SNRI/SSRI, or increasing your dose during winter months. Or just schedule therapy... Even if you don't have a specific goal to work on, talking to someone can help ground you

I know it's nothing groundbreaking (and things we all should be doing more of), but depression is depression... You can reduce symptoms through good habits and coping strategies, but as I'm sure we both know, it both is and isn't as simple as that

Just try to refocus on whatever helps you and be as active as you can going into it