Whether your story is still in your head or already on the page, transforming it into movie material means first creating a screenplay. The most important consideration is remembering that you are working in a visual medium. Unlike written literature, you need not concentrate so fully on the structure of your sentences and weight of your metaphors. Let the actors tell your story.
Writing for the Big Screen
Create the story. Before you can turn an idea into a movie, you will need to follow basic story elements of structure, setting and plot. Make the audience or reader care about what is going to happen to the characters. Lead your protagonist through each scene in a sequential order that makes sense and builds to a climax or conflict. The resolution of the conflict is the end the story.
Structure the screenplay in the correct format. Have scene headings (sluglines) at the beginning of each new scene, character names in capital letters, adverbs describing emotions set in parenthesis. Include references to voice-overs, parentheticals (actions simultaneous to an actor's dialogue), and on- and off-screen sounds. Check out ScriptFrenzy or SimplyScripts for specifics on formatting (see Resources).
Craft each individual scene. Describe each scene's location and the time of day it happens. At the beginning of each scene, set up a visual that producers, directors and actors can translate to the big screen. Include the five W's--who, what, where, when and why--and be clear about what is happening to whom, where it's all taking place and why it might be occurring.
Put the audience inside the scene. If the action takes place in a café, tell us who else is there, what the characters are drinking or eating, what kinds of sounds and activities are in the background. Even if your viewing audience can't smell the freshly brewed coffee, your descriptions turned into pictures can make them think they can smell it for real.
Write fresh dialogue. Unlike the scenes of a book, action on a screen can't expressly explain what is inside a character's head. With dialogue, you should give the audience an inkling to not only what the character is doing and saying, but also what he or she may be thinking. Set the dialogue under the characters' names, spaced according to the formatting techniques described in Step 2.
Build the story to the climax and follow through to a conclusion that ties up the loose ends of all your characters.