When I was studying theatre, good directors always talked about being exquisitely specific in our choices as actors. The character had to be known in the body of the actor, imagined in clear view. Knowing what the character had for breakfast, down to the amount of milk they poured on their overcooked (or undercooked) oatmeal. How much honey, or brown sugar. Bananas, raisins, or something exotic like candied ginger? Or did they had nothing for breakfast? And then, more importantly: how did the breakfast feel in the belly? Inhabiting characters.
In this same way, I think characters in fiction (and probably some creative nonfiction, too) have to be built, drawn, and very specific. Let the audience, the reader, really see (and more importantly, feel) the life of the character.
And I am not talking about eye color.
I was once in a creative writing workshop with a very unskilled writer. (I make this judgment based upon the truly terrible work she had submitted for the workshop.) Her comments on the other writers’ work boiled down to saying she wanted to see more of what the characters looked like. “Like, how tall is he? What color is his hair? His eyes?” She didn’t have much else to say. Until just this moment, I scoffed at how unsophisticated her comments were, and how unimportant those details are in a good story. I still feel that if a writer mentions those pedestrian details, they better be important to the story. But it just occurred to me that this unskilled writer might have been talking about eye color, but meaning something more salient, that is: perhaps she wanted the writers to draw specific characters. Maybe the other writers (myself included) had made fuzzy or unconsidered choices with our characters. We probably needed to go much further, all the way down the alimentary canal.