I generally like to write for a while, and then do character sheets. Sometimes, though, I get stuck on a plot or on a character. When that happens, it sometimes helps to think about real people.
One of the many interesting things about real people: The things they know and why they know them. I know a girl who giggles and flirts and does poorly in school. But she corrects the English teacher on who wrote which classic, and she can identify the painter of quite a few major works, because her parents love books and art.
Although real people don’t always stand stereotypes on their heads, it still surprises you what people know and why. I know how to change a tire because I thought I should. I know that the secret of representational art is to draw what you actually SEE, not what you 
know is there, because I took an adult class for fun. My grandmother taught me how to untangle yarn and jewelry chains. I used to know how to build macros in DOS because one of my nephews who was early into PCs told me I should.
Real people have whims, relatives, and imperatives outside your acquaintance. Real characters have the same, outside your narrative.
So, if you need for someone to know something, find out how and why they know it, and drop a little something about that earlier. The guy who untangles a delicate chain stayed with his grandmother a lot when he was a boy. The woman who safely eases a snake out of the way grew up in the country or volunteered at the zoo.
Remember that movie, THE POSEIDON ADVENTURE? Where the narrative group had to know how far underwater they had to go to get to safety? The fat old rich lady turned out to have been a champion underwater swimmer in her youth. Surprising but reasonable.
You know. People.
A WRITING PROMPT FOR YOU: Write down three things your character knows and why.
MA
Dan Antion
August 28, 2017 at 7:37amIt is a curious thing, to know why someone knows something. With the way technology has changed things, there’s a whole bunch of things people today will never have to know. That might take some explaining.
Marian Allen
August 28, 2017 at 8:24amThat’s always been the case. Ray Bradbury, in HAVE SPACESUIT, WILL TRAVEL explained how his science fiction teenager knew how to use a slide rule by giving him a “crank” father who taught him.
Alicia Butcher Ehrhardt
August 28, 2017 at 6:46pmAnd can use at cross purposes, for some nice bit of conflict, and some foreshadowing: man belies X because of something his grandmother taught him, and not-X because of what a good friend went through. Now X comes up in HIS life, and he has to figure out how to choose. Because up until now, the unresolved conflict didn’t need resolving, but now it is very important to his immediate survival.
Take character, poke with stick.
Marian Allen
August 29, 2017 at 7:49am“Take character, poke with stick.” ROTFLOL! Poor characters! But you’re absolutely right. All the external conflict in the world is just “one damn thing after another” without that INternal conflict putting guts into the gears.
A.C.Flory
August 28, 2017 at 9:55pmThis is probably one of the most under-rated issues in writing. A character’s motivation is never a simple, causal relationship between event and reaction. Each choice, each decision is the result of a lifetime of seemingly unimportant choices that together build into the motivation for a /person/. A plot that doesn’t show that organic motivation will never give readers an ‘ah hah’ moment.
Love this. Thanks. 🙂
Marian Allen
August 29, 2017 at 7:54am~nods~ You put five characters into the same situation and, unless it’s a situation they’ve trained for and trained IN, they aren’t going to react the same way. Even then, they aren’t going to think, feel, and REact the same way. Just one example: I adore THE AFRICAN QUEEN, and how the missionary lady is the one who figured out how to torpedo the German ship because the German soldiers broke her brother’s heart and caused his death. Her missionary courage and determination and ability to make do + her heartbreak and rage = something you would never have expected but totally believed.