One of the current terms familiar to most editors and many writers is "narrative arc." Narrative arc and plot are directly related but they are not the same thing. And the arc is closely related to the motivation of your characters. What does your main character want? What keeps her from getting it? How does she finally triumph (or get defeated) in the end?
The basic narrative arc looks like a pyramid. The line at the bottom is the chronology of the story, the left-hand third rising to the apex is the complications, the right-hand third descending is the denouement. Of course, the apex doesn't have to be in the middle and many stories go up and down as the protagonist gets closer to what he wants and then it slips away (the film Casablanca is a classic sample of one kind of narrative arc where the hero keeps thinking he will get the girl, then she slips away, comes back, slips away.
But in any fiction, the character has to undergo some big change, be it triumph or disappointment. Without it the story falls flat.
Note that many fiction writers do not plan out the narrative arc before they write the story or novel. Once they have a first draft, they go back and read each chapter and see where it falls on the arc. Robert McKee, a famous script doctor, recommends assigning a plus or minus to each chapter to indicate whether the action is rising tension or falling. It's a great thing to do on your plot line. More on that tomorrow.