Narrative

Structure

Most film structures support Todorov's theory which says that all film narratives follow a three part structure:
Equilibrium- everything is normal and balanced.
Disequilibrium- There is a disruption.
and then back to equilibrium when everything is all fine and happy again.

Let me give you an example of this using the film, Pirates of the Caribbean. It starts off like any other Todorov theory following film with everybody happy and everything fine.
Then there is a disruption in the perfectly happy world when the pirates come and kidnap Kiera Knightly.
Finally at the end all is well again when kiera knightly and orlando bloom fall in love.
And there you have it. A perfect example of Todorov's theory.

Characters

The theorist, Vladmir Propp, came up with the theory that all films only have a certain number of characters. For example the Hero, Villain, heroine, father, and the donor. They also have certain characteristics to identify these characters.
The Hero often leads the narrative, he does not neccessarily have to be male or have super powers.
The Villain usually conflicts with the hero and looks wierd or different.
The heroine is usually female (but can be male if the hero is female) and is usually pretty and is some sort of prize for the hero.
The father character is the authoritive figure in the film.
The helper is the wingman of the hero, for example Robin is Batmans helper.
The Donor helps the hero in some way an example of a donor is the butler in the film 'The Dark Knight'.