I've learnt a good technique where I just work on being angry. Doesn't matter what about, even just at myself for being depressed. When I get to angry, I'm not feeling despair anymore. I allow myself to focus on being angry for a while but then that turns into frustration. Then I just become annoyed. And before I realise I'm not depressed anymore.
I know all that is a lot easier said than done but over the years I have got better at it.
Another tool I use is to make a list of 20 things I'm grateful for in my life. At first I can't think of anything, but I make myself work at it and start to remember some good things. Good things that I should be happy about.
I realise not everyone's depression is the same but these tools work for me so I thought I'd share.