Not sure if this has been discussed already, but I awhile back I discovered a fun way to learn more about your characters. Go to the website: https://www.16personalities.com/ -and take the personality quiz from the pov of your character(s). The quiz is really meant for people to take it themselves, but I figured it was a fun way to get to know your character as well. When you finish the quiz it'll show you multiple pages at the end filled with statistics and information about that specific personality type. I find it super interesting and useful, and will plan on doing it again for each of my major characters. Let me know if you guys try it out, and what your characters got! I did this for my MC, and her personality ended up being "The Protagonist" (ENFJ-T)
I might use it. I know my characters fairly well but it is always good to have a deeper understanding of how they work.
I don't tend to use these, or make character sheets, or anything like it. I prefer to let them grow organically, and keep it all in my head until it's in the actual story. Although, I tried this one just now, and I got some good use out of it. I got a better sense of who my character is. I learned that he has a strong, pretty well defined personality that comes through in the writing, but weak and nebulous motivation. He also needs some added depth and detail. Interestingly he got ENTJ-T, "Commander". Fits nicely with him being a dimestore supervillain and the leader of a small crew.
These are always fun! Of my two heroines, one is ESFJ-T, "Consul". The other is ESTP-T, "Entreprenuer". I'm honestly a little surprised at both of these, but reading into it, they both make a lot of sense.