Cheryl Klein, editor at Arthur A. Levine Books (think - Harry Potter) and author of SECOND SIGHT: AN EDITOR'S TALKS ON WRITING, REVISING, & PUBLISHING BOOKS FOR CHILDREN AND YOUNG ADULTS, has gathered two key resources in her blog post "My Two Favorite Writing Things This Month," which you must go experience.
The first is Trey Parker and Matt Stone, the creators of South Park and The Book of Mormon, talking to a freshman class on writing. The second is DAVID MAMET'S MEO TO THE WRITERS OF "THE UNIT."
GO READ/SEE. I'll wait...