Many will tell you it's the title.
Interesting chapter headings, of course.
In Internet discussion groups and during workshops for authors, many writers throw out dull, limp, convoluted book titles for critique, only to be advised that there's a better one right around the corner. Here are several techniques for coming up with enticing titles. The next time you're waiting in line at the supermarket, or you're visiting your favorite bookstore, scan the covers of magazines. Compile a list of clever titles that capture your attention, even if the articles have nothing to do with your book. Sometimes you can substitute one or two words to come up with a title that's a perfect fit for your topic.