What I do:
Seize every available window of opportunity. It might only last for a few seconds, and if I lost it? Easily out for hours or days before the next one would hit.
Even so, I might only make it a few minutes before my vision went sideways and my legs went out from underneath me. So use those minutes and make them count. Keep moving and do as much as I could to help push me forward & lift me up (food, bathing, music, get out of the house // grounding, centering, focusing on the real world instead of the Grief&Pain <> Nothing&Fog).
Any focus is better than no focus. If I could plug myself into movies or videogames? I might not be doing anything worthwhile, but I wasn't getting sucked into my head. The less I was sucked into my head, the easier & longer I could stay out of my head.
Movement. Sounds stupid, but even just walking a few miles a day, plus &/or anything extra (dancing while cooking, yoga/gymnastics in between sedentary activities, sit-ups or twists whilst watching a film, singing, parking further away -looking for the last spot in the car park instead of the closest spot- than I otherwise would, using fine motor activities (drawing, writing, lockpicking) if I was too numb/exhausted for gross motor. Not wanting to do it? Mean I still did it. Because not wanting to is a step UP from not being able to.
Hedonism. So little -if anything- feels good (except laying perfectly still / not moving / sleeping) that I actively search for things that even kinda sorta feel good. Cold drink and hot shower. Soft clothes. Loud music. Being silly (even if highly sarcastic silly). Anything and everything I can find to connect me to the here & now. If only for a moment? No matter. 1 moment is better than zero.
Lower stress. Yup. Just like for every other symptom. Lowering stress levels just helps.