Most of my advice stems from the premise test:
An <ADJECTIVE> <PROTAGONIST TYPE> must <GOAL> or else <STAKES>. They do this by <DOING> and learns <THEME>.
Most movies break down into some form of this. It may follow a group, not a single protagonist (NASHVILLE), the stakes may be low, purely emotional, or metaphorical (BEFORE SUNRISE, MY DINNER WITH ANDRE LAST YEAR AT MARIENBAD), but they will be there and deeply felt.
This is where someone usually calls me out as a hack peddling a formula. This used to bother me, it doesn’t any more. This is just how stories work, some exceptions exist, but you have to dig deep to find them.
Sentences have adjectives that modify nouns that do verbs. Stories have protagonists that pursue goals or else stakes.
This need not be taken as a universal truth, it’s just a convenient and simple way of analyzing a story.
An <ADJECTIVE> <PROTAGONIST TYPE> must <GOAL> or else <STAKES>.
This must be set up in the first 25% of a script. No one need ever say “I’m an alcoholic lawyer who must win this case or lose my soul” (THE VERDICT) but the first act should communicate that as clearly as if they had.
This is where 60% of stories fall apart. The stories fail to set up rooting interest, I’m not clear on what’s going to be pursued, so the middle loses urgency.
Goals and stakes allow us to follow a story. If we like a protagonist and no what he wants, then we can easily track the second act by how each sequence gets him closer to or further from the goal. If we can’t, then it’s really hard to make each individual scene feel necessary and urgent.
Exceptions apply, but this is a generally useful rule. Make sure you first act sets up a rooting interest, if it doesn’t, it’s going to be hard to keep things clear and sustain an idea over the next 70 or so pages.