The opening of your teaser should give readers a taste of the story's main elements and leave them wanting more. Focusing your attention what is at stake for the characters, such as what they stand to gain or lose from the conflict, can reveal the heart of the story and generate curiosity about the potential outcome. For example, the teaser for Kate Morton's "The House at Riverton" creates intrigue and mystery about a suicide and its consequences: "On the eve of a glittering society party, by the lake of a grand English country house, a young poet takes his life."
Because different types of books emphasize different literary elements, you'll need to tailor the tease to fit the book's genre. For example, thrillers are typically driven by fast-paced plots, so a good thriller teaser would emphasize the story's action. By contrast, a romance novel teaser might be slower paced, drawing on the relationship between the two main characters and the obstacles they face. Your use of diction, or word choice, and tone also depends on the book's genre. While a somber tone and dark imagery might work for a mystery novel, it wouldn't be as effective for a humorous book.
The worst thing your teaser can do is give too much away. Sharing significant plot points, mysteries and reversals in the story can reveal enough of the book that readers actually might lose interest before they even open it. To avoid spoilers, editor Frances Reid Rowland suggests keeping your teaser at a maximum of 150 words. This length requirement will force to you to use concise, selective wording and describe the most important characters, conflicts and ideas in the book, giving readers only what they need to know to pique their interest in the story.
Teasers should avoid subjective language, including phrases like "wildly brilliant" and "astonishingly original." Use of excessive descriptive language can make the story appear cliched or unoriginal, or, if you are an independent author promoting your own book, make you seem self-satisfied. Instead, add variety to your sentences to increase the teaser's sense of drama. Pearson Publishing suggests rewriting your sentences to include adverbs and adverbial phrases, and using different sentence lengths and structures to add tension to your summary. Writing multiple versions of your teaser can also give you options for choosing the one that best showcases the story's premise.