As a depressed fuck, I have done a lot of reading around this. The consensus seems to be:
(1) As you go through your day, stop to notice things that are nice and that you like. Examples include the sky being pretty, the wind feeling nice, how your cat is next to you and your teamug is steaming as you write (the book author had a cat and liked tea), etc. The goal here is to train yourself to (1) stop, (2) notice nice things, (3) experience nice feeling. You're literally trying to form a neurological habit here to counteract the automatic focus on the negative we come with bc evolution thought it would be nice to watch out for tigers.
Sub-tip from CBT, if the acronym gives you cognitive behavioral therapy and not cock-and-ball torture vibes: CBT claims that when you're training mental habits, it works better if you make a note of how many times you did the thing and keep a log. There are apps for this, or you can make tally marks in a small notebook you carry in your back pocket, but the recommendation is to literally get an old school mechanical clicker counter so you associate a tactile and a sound element with having done the thing. Noticed clouds - check. Over time, the log you keep of "times-per-day i did the thing" should show evidence of progress which should please and motivate you. If I went this route, I personally wouldn't use an app because I don't want to create an association between success at a task and feeling good on the one hand and the act of pulling out my phone on the other, but you do you.
(2) Self-reward intermediate progress. This comes in two varieties:
(2.1) Self-reward intermediate steps. When you are on the right track, tell yourself you're on the right track and feel good. This could either be when you're in the middle of a project or when you've had a set-back but you're still on the right track and things aren't completely fucked up. For instance, tell yourself, "It's (still) good I stuck with this for half an hour" or "I did well to have made my bed." The key here is not to tell yourself you're great or the best or whatever but literally that you approve of having done a thing, that it was a good thing to have done (that part of) it, that it works out nice now that the kitchen sink is clean and has no dishes in it, etcetera. "I'm on the right track" "at least i'm not still wallowing in bed" etc.
(2.2) If you do something that's a major milestone, self-reward like whoa. The goal here is to give yourself the good chemicals. Made it to the gym where before you were self-conscious about going there as a fat fuck? Mastered a skill, completed a project? Tell yourself you did an awesome job. Laugh. Do a "yessss" pump thing.
The key is not to lie to yourself. You made it out the door but you feel like you should be able to do more? "I should be able to do more, but I still did well to have put on my running shoes and gotten out" etc.
Hope it helps.