If you’re struggling with plot structure, take a playwriting class. One of the first things you learn, before stage directions and sharpening dialog, is developing a plot.
It boils down to this: Character One wants A, Character Two wants B. A and B oppose each other, so Characters One and Two compete until a character wins.
I’ll put it in story terms.
The protagonist wants to save his family. The antagonist wants his family locked up in prison for the rest of their lives. These wants oppose each other, so the protagonist and antagonist compete against each other until the family is saved or the family is locked up in prison for the rest of their lives without any threat of being released.
The character does not need to save his family. The character does not have to save his family. The character wants to save his family.
Despite dictionary definitions, want and need are not the same thing. Need is a requirement for survival. A club needs members in order to survive. Your character needs food, water, clothes, and shelter in order to survive.
Want means to desire, to value, to hunger. When a character wants, he aims to improve the quality of his life. He wants to save his family because his family’s survival increases his quality of life.
Shouldn’t a character save his family because it is the right thing to do?
A character is motivated to work harder and endure more hardship when he’s invested in the goal. A character’s motivation cannot come from outside himself. It must be a want from within.
Simply put, your character must be selfish. And selfish is not a bad word. Selfish means for oneself. It doesn’t mean only for oneself and it doesn’t mean harming others in order to gain for oneself. There’s another word for that: greed.
I’ll come back to this.
This may seem contradictory to what happens in many stories we read or watch. Characters proclaim it-is-the-right-thing-to-do this and it’s-not-for-myself-but-for-everyone-else that before charging into battle.
But pay close attention not to what the character says but on what he does. When he saves his family, does he really do it because is it the right thing to do? Is he really saving his family selflessly and only for them?
Look at his actions. How passionate is he about saving his family? How does he feel about saving his family? How invested is he in saving his family?
That’s a person who wants to save his family. That’s a person acting selfishly. That’s a person who acts from within.
So how do we choose sides? What makes a protagonist and what makes an antagonist?
It’s a battle between selfishness and greed. A protagonist’s actions are selfish, while the antagonist’s actions are greedy. An antagonist resorts to dishonest actions that harms and misleads others into cooperation. Because it is morally correct for our actions to not harm others, a greedy character becomes the enemy.
It’s okay to want to like and dislike a character in a story. It’s okay to selfishly cheer on a character. It’s okay to want a character to succeed from within yourself.
You and your character have something in common: you both want.