Simple and Sparse
The writing style of The Usual Rules is simple and never flowery—the narrator describes the things Wendy goes through as they happen, and shows her feelings (whether ugly or pretty) in a stark, truthful way. The writing style is so simple, in fact, that it eschews quotation marks for the dialogue, making the book read almost like one long stream of consciousness (except it isn't in the first person):
Sissy, he said. Is it true God sees everything.
I don't know, Louie. What do you think?
Then he'd be watching even when I poop.
He probably has more important things to do, Louie. There's a lot of people to keep track of. (16.9-12)
By getting rid of quotation marks and using the most unadorned language, the book allows the reader to take in the story in its most simple form—which is good, because the themes of the book are quite complex.