Fractals are mathematical images that are composed of identical images that form much larger images. Stories are the same way.
The overall story has a goal and each Act has a goal as well. Digging deeper, each scene has a goal too. By constantly focusing on telling mini-stories that make up a larger story, you can tell a coherent and compelling story.
Every story poses an initial question that gets answered in the end. In “Die Hard,” the initial question is whether the hero will get back with his wife or not. In the end, he does get back with his wife.
Yet every part of the story works against him getting back with his wife. In Act I, he finally meets his wife, only to get into a fight with her.
In Act IIa, terrorists have taken over the skyscraper so the hero’s goal is to save her by contacting the police, which he finally does at the midpoint of the story. Of course before he can contact the police, he has to single-handedly fight and kill several terrorists first.
In Act IIb, the hero’s getting closer to getting back with his wife by stealing the villain’s explosives, but then the villain discovers the hero’s identity and seriously wounds him, making the hero’s goal of getting back with his wife look doubtful.
Finally in Act III, the hero defeats the villain and gets back with his wife.
Notice that in each Act there’s a goal, but that goal supports the main goal of the hero getting back with his wife. In every story, define the main goal and then define the goals of each Act.
In the horror film “Don’t Breathe,” the hero wants to get enough money to leave her abusive mother and take her little sister away to save her as well. In Act I, the hero decides to break in to the home of a blind man who reportedly has a large amount of cash hidden inside.
By the end of Act IIa, the hero has found the money and his looking for a way out of the house without the blind man catching her.
In Act IIb, the blind man has caught the hero and now her goal is to escape from him.
By the end of Act III, the hero has escaped from the blind man and gotten away with the money so she can start a new life with her sister.
Think of your story’s overall goal, then think of a mini-goal at the end of each Act that represents a stepping stone towards achieving the overall goal.
By constantly focusing on your story’s overall goal, you’ll likely write a tighter, more coherent story. Just watch a bad movie to see how the goals of each Act often fail to support the overall goal, mostly because that overall goal is not clearly defined.