The purpose of a scene is to move the story along. However, the only way a scene can move the story along is if it also brings the audience along, and audiences won’t follow along if a scene is predictable. So if you want to keep your story moving, make sure every scene surprises the audience in some way.
The best way to add surprise in a scene is to shatter expectations of both the audience and one of the characters. Do this in every scene and this will keep your story moving forward with full audience engagement.
Think of what a character expects and emphasize this so the audience believes it too. Then find a way to shatter that expectation.
In an early scene in “Legally Blonde,” Elle (the hero) thinks she’s going to dinner where she expects her boyfriend to propose to her. Since that’s her expectation, it gets shattered when her boyfriend dumps her instead. That shattered expectation keeps the story moving because the audience wants to know what will happen next.
In the opening scene of “Invisible Man,” the hero is a woman trying to sneak out of the house without her controlling boyfriend knowing about it. Her expectation in this scene is to get away so to shatter that expectation, her boyfriend discovers her escape and nearly stops her.
Now imagine how these scenes in “Legally Blonde” or “Invisible Man” would work without shattering a character’s expectations. If Elle in “Legally Blonde” expected her boyfriend to dump her and he does, that would be boring. If the hero in “Invisible Man” expected her boyfriend to nearly stop her from escaping, there would be no suspense in hoping she would get away without being detected.
When writing any scene, identify the expectation of the main character (and the audience) and then shatter it somehow. Do this and every scene you write will keep your story moving and your audience following every word.