When I was in a very deep, dark space some years ago, I started a gratitude practice of thinking of 3 things at night that I was grateful for. It gradually turned into all the things I could think of at the time. Then, because I was struggling so badly, I started looking around me during the day and saying that I was grateful for the most basic things as a way to focus my mind away from the pain I was in and to train myself to see differently. “I am grateful for grass.” “I am grateful for paint.” “I am grateful for this paved path.” That sort of thing.
Also, because I wanted to have at least 3 things to remember at night, I started paying attention to what was happening during the day that I could be grateful for. That started me being aware during the day of what was happening that I was grateful for. It started me being aware on a daily basis of at least some of what is going well, no matter how small, and I often just say thank you for it, even “thank you that I did not fall when I tripped just now!” (more than once!). I have even sometimes been grateful for the painful, uncomfortable feelings I have, because they are part of the whole human experience and they have taught me a lot.
I know that my days are so different now, for many reasons, but I find an amazing number of things to be thankful/grateful for and that keeps my mood in a better place. It has certainly shifted my anxiety and depression to a much lower state.