Here's one of the shortest (and best) lessons on writing for any genre of fiction, from Stephen King:
"Really scary books (“The Exorcist” is a good example) succeed because we come to know and care about the characters. I like to say, “It's the PEOPLE, stupid” — NOT the monsters!"
There's more from him here, including an excerpt from his most recent novel, "Duma Key," and a six-minute interview on the "Today" show.
(There are loads more tips and techniques at www.yourwritingcoach.com, and also sign up for our free monthly e-bulletin for more on creativity and productivity--send a request to [email protected])