For me it is ultimately the cold hard reality of taking responsibility for myself rather than doing nothing and expecting not to feel rubbish.
For example, it's having the control to not listen to sad songs if I am feeling sensitive as I know this will make me feel worse. No matter how much I want to listen to them.
It's avoiding things that might make me feel worse. Or if I have to do or think about these things then I promptly do what is needed and then I have to be very strict with myself to focus on the new time, day. For all I know that could be my last day.
It's prioritising taking care of my self. Not in the sense of going off and having a spa day. But in the sense of whereas before I might have engaged in self defeatist behaviours (not eating, suicidal tendencies ect) I try my best to have much more control. Because, I know I have to look after myself if not I will not get through the even worse times.
I try to take care of my emotional health in the way I expect my children's to be taken care of.
It's making time. I try my best to find one hour a week to do a hobby at home I enjoy. Again, with so little time and energy it is hard and requires discipline but it helps.
Other than that, distractions, good relationships, a bit of wisdom and remembering that everything is temporary including life.
So there we go. After a life of relentless depression, suicide attempts, having phases of putting all of my energy into resisting suicide and volunteering as a counsellor that is what I have arrived at. It is being in such control of yourself and behaving in a way that isn't dictated by your feelings.
It doesn't make depression go away. It does make it easier to cope with.