What's the last thing you researched for a story?
Names of flowers. I decided to name all the characters in my latest story after flowers, then decided the world it's set in has no concept of gender. These are perfectly reasonable decisions on their own, except for the small problem that it's really hard to name characters who aren't female after flowers, and since none of the characters are female, I need to find non-gendered flower names. For every single character. No matter how minor. This was a terrible plan but I refuse to go back.
Do you tend to have a lot of characters in a story, or just a few mains?
I usually have 2-4 main characters, and not a lot of side characters. There are a few exceptions though, like Impossibility which has seven main characters.
When/if you make up a language, do you just whip it all up as you go, or do you take already existing words and mix them up with other words (made up or not)?
I usually completely make things up as I go. Occasionally, when I want a fantasy place to be clearly inspired by a real place, I'll throw a bunch of random words into google translate, and combine bits and pieces of words into a name that sounds like something from that language.
Do you tend to have detailed side characters, or just ones with vague personalities? How much effort goes into the story of your non-mains?
Like Worst, my side characters either only exist briefly to fill a purpose, or become main characters, with no in-between.