Learn how to read a script, find its core, determine your vision, communicate with writers, actors, designers, cinematographers, editors, composers, and all the members of your creative team in order to insure that your vision reaches the screen.
This book is an excellent take on the art of directing films. Mark Travis is an amazing teacher of "the big picture" of filmmaking. He's a great teacher too, and I would highly recommend attending one of his directing workshops if he comes to your town.
I'm tempted to start a new "shelf" called "using" because I've been not only reading this book but also using it in the pre-production and production of a film I'm shooting this summer. The book has been tremendously helpful in terms of casting, re-writing, rehearsing, and general organization and collaboration with cast and crew.