Create many potential paths to a defined goal. The first rule of suspense is to leave the plot open from the onset, but with a more or less clear objective. Detective novels follow this rule closely: The detective must solve a particular crime, but how he will solve it or what paths will unravel the mystery are unknown from the beginning. Hardy Boys novels consistently follow this rule, often resolving a known crime by an unexpected path.
Instill a sense of progression and movement in the plot. In Shakespeare's Romeo and Juliet, readers sense from the beginning that the couple will fall in love and, likewise, sense the way in which this will be problematic: They come from rival families. This sense of movement makes readers tense and draws them into the plot.
Increase the intensity of the story as the reader approaches the climax. Raise the stakes of the crime. In literary mysteries, such as those by Agatha Christie, the perpetrator of the crime that the detective hopes to solve commits additional murders, or threatens those who are trying to catch him. As the detective comes closer to solving the crime, he also places himself in greater and greater danger. This heightens the excitement of the reader as he approaches the climax of the story.
Focus on details as the story progresses. Turnings of keys, door knocks, thumbs, clothing caught on hooks---these are the small details that raise the readers' attention level and draw them into the story. The more small details are included in the story, the more the reader will tend to imagine outcomes and possibilities, and this increases a sense of suspense. Most suspenseful works requires several chapters to cover the outcome of the mystery at hand because a successful redaction requires many details.
Finally, authors of suspenseful literature create close calls or "red herrings," a literary term for false solutions. This keeps the plot from becoming predictable and keeps readers on their toes. An author of a suspenseful work might progressively disprove all the usual suspects, leaving the reader wondering in greater anticipation who could have committed the crime. When readers' expectations are upset, they begin focusing with greater intensity on all clues or aspects of the plot, and this focus creates an atmosphere of suspense.