To write a screenplay, divide the story into clear acts that mark changes in the main character, her desires and the outcome of her journey. Ensure the ending of the story is satisfying, though it needn't necessarily be positive. Supply supporting characters, allies and villains that add dynamism and intrigue.
Screenplays are typically divided into three acts. The first introduces the major characters, the setting and relevant tensions. The second advances the story to a high point in those tensions and pits the main character against a series of successively difficult challenges. The third act demonstrates how those conflicts are ultimately resolved.
After the acts are broadly outlined, each scene needs more detailed development and compelling, pared-down speech. Unlike many other forms of creative writing, screenplays must not contain any prose. The writer can only include those things that are heard and seen on screen. Additionally, the opening 10 pages should provide a flowing introduction to the story that hooks the reader.
As format expectations regarding screenplays can be extremely exacting, the writer should consult industry standards concerning details such as margin size, font and line spacing before submitting her manuscript, as even the smallest such inconsistency can be grounds for rejection. To iron out potential issues, consider using software products such as Final Draft, Movie Magic or Celtx.