Plot involves at least three primary threads: Dramatic Action, Character Emotional Development, and Thematic Significance.
Of these three elements, writers are equally divided between those who begin a project by concentrating on the Dramatic Action and those who begin with Character Emotional Development.
Dramatic Action writers tend to thrive on the excitement of what happens in the story. The first draft of a Dramatic Action writer is full of excitement with lots of conflict, tension, and suspense, twists and turns, chases and confrontations, and usually contains little character development. Often, a reader's comment of this first Dramatic Action draft is: "Why should I care?"
Writers who prefer to explore the different aspects of a Character's Emotional Development delve into what makes her tick, her feelings and emotions, her loves and hates. The first draft of a Character Emotional Development writer tends to be full of insight into the human psyche, with very little happening in terms of Dramatic Action. Often, a reader's comment of this first Character Emotional draft is: "When is something going to happen?"
Far fewer writers choose to begin with the Thematic Significance thread. These writers usually have a message they wish to impart, but not much of an idea of characters or what will happen.
Wherever you begin writing, by your final draft, you have an idea of the deeper meaning of your story, what you are trying to say and the ways you have attempted to communicate that meaning through your story to your audience.
Crystallize the meaning into two specific universal themes and improve your chances of creating a classic blockbuster story.