Attend a film school to learn your craft. This is an effective way to gain the foundational knowledge in film history, film theory and directing that is necessary to become a good director. If you don't attend film school, you should watch hundreds of classic, foreign and contemporary films and study reference books such as "Making Movies" by Sidney Lumet, "Who the Devil Made It: Conversations with Legendary Film Directors" by Peter Bogdanovich and "On Directing Film" by David Mamet.
Work on movie sets. The best way for an aspiring director to learn what happens on a film production is to work on a set. There are many production assistant, or PA, jobs available on a movie set. PAs are tasked with a number of duties, including lifting equipment, relaying messages, taking food to the cast and running errands. But the biggest value of working on a set is seeing a director in action and learning how she works with the cast and crew.
Read scripts. As a director, one of your most important skills is knowing how to read and analyze a script so you can break the story down. Many Internet sites have script libraries that let you download scripts in PDF format and read them. As with watching films, studying classic scripts gives you insight into how a director interpreted the written material. In addition, you will need to be familiar with script structure to effectively work with a writer when you start directing your own films.
Take an acting class. Acting classes provide you with insight into the acting process, the different methods they use for performances and how to talk to actors in a creative and meaningful way. It's nearly impossible to direct a good film without getting the right performance from your actors. An acting class helps you understand the methods actors use to access a character, which facilitates your ability to elicit the emotions you need when you are directing. New York and Los Angeles offer many types of acting classes, some that follow classic methods taught by Stella Adler and Lee Strasberg, and others that are focused specifically for aspiring directors such as the Judith Weston Studios for Actors and Directors in Los Angeles, which offers an acting for director's workshop.
Practice your craft. Becoming a good director is a process that develops over time, but you have to start by directing something tangible. Write a short, 8- to 10-page script that you can film in one location using actors willing to work for free. You will need to rent a camera -- digital cameras are typically less expensive -- and put together a small crew. You can advertise for cast and crew members in publications such as "Back Stage," "Hollywood Reporter" and "Variety." If you don't have the money for a short film, shoot a scene from a favorite script and re-imagine it with your own vision. The goal is to become comfortable working with actors, and learn how to block out and compose scenes.