Imagine you're riding in an elevator with a potential reader of your book. You have 20 seconds before the elevator door opens and your companion leaves. What can you say to compel him or her to walk to the nearest bookstore and buy your book as soon as the door opens? The answer is the heart of your excerpt.
When selecting sample passages, don't automatically take your excerpt from the front of the book. Material from a book's introduction can be dull for an unfamiliar audience.
More hints for a compelling excerpt: