I allow myself time to first feel for a while. Emotional release. I might cry it out or write it out. Any way to try to make sense with what emotions I am feeling and why they are there.
Then I go back to my list tittled "Things That Make Me Happy."
I review it, maybe make some addendums and pick a few things off of my list to implement within my day. No matter how big or small.
It may be something as simple as going to my favorite coffee shop and ording that expensive latte I like. Reading a good book. Cuddling with my dog. Anything that is on my list that brings me even a small tinge of happiness works wonders.
Lastly, I try to connect with someone that I know is positive and encouraging. This is usually the hardest part to convince myself I need to do but I have never regretted it afterwards. Connection is important because when I am feeling low, I feel alone in that. I think a lot of people do. Sometimes my intention is to laugh and have fun with that person. Sometimes it is like a therapy session where I feel the need to talk things out. Sometimes it is as simple as doing something nice for someone else to see a smile on their face. All of these things bring me joy. I try to pick each person accordingly.
Also, I do like to read self help books and have been trying to enstill some of their teachings and concepts. I have read many but my favorite so far is Addicted to the Monkey Mind by JF Benoist. It's about taking control of your thoughts and no longer letting your inner critique run the show. Might be worth a try. It has helped me tremendously.