For the writers out there, here's a tip on character building I wanted to share.
Chances are your story is going involve a calamitous change to the life of your main characters, or depending on the scale of your story perhaps everyone is about to have a serious problem that needs solving.
One thing I did before I started writing DARWIN was to jot down, from each character's perspective, what they did from wake-up to bedtime the day before the book begins. This proved immensely valuable to me in understanding who these people were and what their lives are like. Plus, and somewhat unexpectedly, it helped me flesh out a ton of details about the world they live in. Until that point I'd mentally treated worldbuilding and character development as two separate tasks.
Originally I'd intended to write up their "typical day", but it occurred to me that specifically choosing the day before the story begins would pay higher dividends in the book itself. What happened yesterday is still on the mind, still relevant, still being talked about. Even if the opener of the book changes later on (for DARWIN it did, in fact), exercise still yields plenty of useful details for your characters and their world.
Stories often yank their characters from their ordinary life and into the extraordinary. Your understanding of what ordinary is will help your ability to think as your characters do. Because often, perhaps all the time, a person's first instinct when faced with change is to find a way back to normalcy, to comfort. Change can be scary as hell. We just want things to be how they were, even if we know that's impossible.
Give it a shot if you like. You could write this up as a full blown scene, a diary entry, whatever works for you. In my case it was just quick bullet lists, no more than a page long each.
Standard disclaimer for any writing advice: There's no rules, only tools. Do what works for you.