The analogy between a screenplay and a blueprint is a cliché but also accurate. It’s a document in one medium that articulates how to make something in another medium. A layperson may not understand it, which is why architects often make models of their designs. So, what makes a great script?
  1. Language
    A screenplay should still be well-written, but traditional literary definitions don’t always hold because so many aspects of a script only feel evocative to professionals familiar with the form. Like an orchestra reading musical notation and understanding it’s a symphony.
  2. Precision
    Screenwriting is a laconic form. It uses the minimum number of words to evoke the maximum experience. Like poetry, every word matters. Unlike poetry, people will spend millions of dollars and thousands of hours turning those words into a movie.
  3. Structure
    How the story is built. Exactly where it starts, exactly where it ends, the specific sequence of events from start to finish. If you don’t understand why this is important, try listening to a long-winded friend tell a shaggy story with no discernible point.
  4. Propulsion
    How events build on one another with increasing force, pulling your attention to the climax. A movie should feel like a boulder rolled up a mountain and released on the other side, each successive scene building with increased momentum.
  5. Character
    Who these people are when the movie begins and how that changes through the story’s events. What’s at stake for them. How they react to conflict. Why they make the decisions they do and how those decisions reveal who they are. The clash between who they think they are and who they might become.
  6. Dialogue
    Like in everyday life, people are defined not just by what they say but how they say it. And, crucially, what they don’t say. A line of dialogue may appear incredibly simple, but how it is performed can be woozily powerful. The words “yes” or “no” are utterly banal, until you ask someone to marry you and wait for their answer.
  7. Tone
    The carefully calibrated balance of comedy and drama, emotion and restraint, lightness and darkness, intensity and delicacy, cynicism and sentimentality, that create the overall feeling of the movie.
  8. Theme
    What the movie is about. How this story told in this sequence with these characters making these decisions explores, embellishes, and complicates an essential philosophical idea.
  9. Metaphor
    As a written document that’ll be translated into an audio-visual experience, scripts use visual and sometimes auditory allegories that will be interpreted by the director, cinematographer, production designer, costume and make up artists, and so on. These are more concrete than literary similes but the effect is similar.
  10. Harmony
    The thing about a good screenplay is all these elements must work together, seamlessly, without drawing undue attention to themselves. Screenwriting makes itself intentionally invisible, like the code that makes your smartphone more than just a fancy coaster.
  11. Inspiration
    Along with all these literary things, a screenplay also has to be a sales document to convince chronically risk-adverse people to spend millions of dollars on it and an instruction manual for hundreds of crew members, including the director and actors, to actually make it. It has to inspire creativity, confidence, and commitment for years of people’s professional lives.