Setting as Character--How to Create Emotion from the Setting in Your Book

Rita is working on a MG (middle grade) novel. She wrote me this week with a good question about how much to use setting in her book.  What's not enough, what's too much? And most important of all, does a story's setting need to be as developed as its characters?

Her story is set on Mars, a hostile environment ("Think adventure movie," she says, "with ava…