The reader will become interested in a story if the viewpoint character has a problem with which the reader identifies. A problem is always caused by a motivation, and therefore motivation is the heart and soul of any story. Somebody wants something and can't get it. The problem arises because he can't get whatever it is he wants. The story ends when the viewpoint character either gets or fails to get whatever he is motivated to get. If the character doesn't want anything, he doesn't have a problem. You shouldn't have more than one motive and one problem in a short story. A good example of a good story is "To Build a Fire" by Jack London, which is amply covered in eNotes. The viewpoint character wants to get to a certain camp where he will be able to get warmth, food and rest. He encounters various problems because of the severe cold. In the end he fails to reach his destination and freezes to death. Look for the problem resulting from the motive in any story and you will see what the story is "about." Readers identify with characters' problems when they involve love, money, self-preservation, revenge, and other such important universal motives.
There are specific plot techniques that writers use to enhance interest and tension in a story.
One common plot technique is a specific use of foreshadowing where the end of the story is mentioned at the very beginning. For instance, a story about your childhood that ends with you chipping a tooth could be opened by mentioning the tooth.
"I was ten years old when I learned not to chew on things that I never planned to swallow, like baseball bats. Coincidentally, that is also how old I was when I chipped my front tooth."
This is a common way to open a story because when the reader knows what is coming, he/she will naturally anticipate the moment when, in this case, the tooth gets chipped. Alfred Hitchcock used this method in many of his films as well to build suspence.
Another plot strategy is related to structure. Structuring your story using short sections can help keep the reader moving along and interested.
Plot is just one element to a good story, however. Using dialogue can also help bring a story to life.
A plot is necessary to keep a reader interested in a story. Enotes defines a plot as "the order of events in a narrative or any other type of story." The importance of the plot lies in how a story follows chronology. For example, a story may be chronological or have flashbacks or be framed. If an author fails to follow the typical plot line (exposition, rising action, climax, falling action, and denouement, or resolution), a reader may become confused regarding the order of events. Once a reader is confused, the chances of their interest being lost is high.
That said, a plot which builds in intensity and conflict tends to keep a reader engaged and wanting to read more. That said, a story which lacks conflict or rising action fails to climax and the reader may see no reason to continue reading.
Therefore, in order to keep a reader interested, a writer must include interesting characters, developing and deepening conflict, and a resolution which leaves the reader feeling a sense of closure.