All those telling details:
What do many writers have in common? A diversity of knowledge? Lots of research books? "How to" pamphlets and magazines and books crammed into shelves and crevices and piled high near walls? Did you say, "all of above?" I bet you did.
The amount of research we writers accumulate could earn us several degrees. I often say my favorite books are the dictionary and the thesaurus, basic details for the beginning and advanced writer. But really, for each individual we introduce, each career, we do our own background checks and bios. For my last short story I read two books, part of another, and a few articles as references: Psychic Discoveries Behind the Iron Curtain, Remote Viewing manual, Are you Psychic? (I'm not), and some here and there articles about telepathy.
For the characters in my novel, I'm back at accumulating details-- have a lawyer, Ronnie, who studied at NYU. I looked up the civil law in NY and CA. I read about landmark cases in women's rights. Sam, another character, is savant-like. So I read David Tammet's stories, two books about being a savant: Born on a Blue Day and Embracing the Wild Sky. Actually, the second book says a lot about our evaluation of intelligence. So I have Sam just retired from a very lucrative business of alternate intelligence and trade testing for corporations and schools. That's just the beginning.
Anyway, you get the picture. We are a well-learned lot. Details are our business, learning them, picking out the best to choose for the story, not giving away or weighing down our work with them, and, most importantly, unfolding them into interesting reads that keep the eyes wandering along our many pages.