The Plot Must Thicken
Actions → Reactions → Further Actions a.k.a. Complications
Actions cause Reactions, which cause further Actions.
These further Actions are known as Complications.
Complications → Conflict
Complications cause Conflict.
Many complications / A complexity of many reasons makes 1 solitary conflict.
Your job in the Second Act is to show and track this complexity of reasons, as they develop.
EG. James, the character, getting into trouble because of his own actions or the actions of others, and then the conflict getting exacerbated by his reactions or other characters' reactions, and their subsequent actions.
STRUCTURE is when things happen BECAUSE of the other.
Killing Your Darlings
Each scene's life must be born inside the womb of a preceding scene.
It's time again to check if an extraneous scene slipped through your outline level.
Remember to be objective. If the scene still doesn't fit, be tough, and take it out.
The End of the Middle
Here, the decision is made.
(EG. Butch and Sundance go to Bolivia. Eliot chooses to rescue ET. Jennifer's mother decides to track the pedophile. Cliff decides they're breaking out of the mental institution.)
The Key Decision that triggers the third act is usually made around page 85.