It’s easy to lose your way when writing, especially in Act II. Here’s the diagram that I use to help me control the plot and structure of a full length feature film. This technique is all courtesy of Syd Field, the master of screenwriting. I would encourage everyone to read his books “The Screenplay” or “The Screenwriter’s Workbook”.
Do the story arc.
Right so Syd Field uses a story called “The Unhappy Marriage”. A young woman, a painter in an unhappy marriage, enrols in an art class and has an affair with her teacher. Against her will she falls in love with him, then learns she is pregnant. Torn between her husband and her lover, she decides to leave them both and raise the child by herself.
This is the setup act, where we learn what the story is about, who the characters are, and why we care about them. Your main character is normally in every scene, and we go through “a day in her life”. So for instance, in this story we could portray the unhappy marriage with a scene of them eating breakfast in silence, sleeping in separate bedrooms, arguing etc. The woman, let’s call her Mary, is a painter, so maybe we could see her releasing her frustration through painting. The TP1 (Turning Point One) occurs when she enrols into the art class. This is the inciting incident; the moment where your main character’s life could never be the same. If we’re writing a 100 page script, then Act One should be approx. 25 pages.