A character is a person who takes part in the action of a literary work. These include your protagonist (main character) and antagonist (evil character), as well as any supporting players in the story. It is important to develop your characters well, but not to spend too much time on characters that are not essential to the focus of the story.
The setting of a story is the time and place which it happens. Authors often describe the settings of their stories to help set the tone and mood. Examples include descriptions of landscapes, scenery, buildings, weather or seasons. Describing the atmosphere at the location where the story takes place will help draw a reader into the feeling you are trying to invoke as a writer.
The conflict is the central struggle of a story and what drives the events and character actions. Typically, the protagonist is on one side of the central conflict, while the antagonist is on the other. While the conflict may be a struggle between these two characters, other conflicts may put the protagonist against the forces of nature, against society, or even inner-turmoil--feelings, emotions or illness.
A story's plot is how the events and character actions of the story relate to the central conflict. In other words, it is why everything in your story takes place and gives each scene and action a purpose in its inclusion. All plots should have a beginning, middle and end. Keep plot in mind when adding additional scenes or characters that may not be necessary when trying to arrive at and solve your story's central conflict.
The theme in a story is the controlling idea or underlying meaning that the author intends for the reader to understand. For example, the theme of a story may be used to show the writer's opinion on a topic or to illustrate their perception of human nature. Various figures of speech can be used to emphasize the theme of a story, such as symbol, allusion, simile, metaphor, hyperbole or irony.