On the typical back cover of your book, you will have a few testimonials, a few sentences to convey the message about the content of the book, and a few sentences to talk about yourself and your expertise. In those few sentences, you must excite a potential book buyer enough to buy.
Writing effective cover copy is an art and is best done by professionals with years of experience in writing sales copy, especially for books. Whatever is said on the back cover can be utilized in a number of other sales opportunities, such as on Amazon.com or sell sheets.
Testimonials should be written professionally as well, and the person endorsing the book can choose which message he or she feels comfortable with.
Too often, cover copy is written by the author and tends to be wordy. The style of writing in a book is different from the short sentences and high-impact wording required by cover copy.
Expect to spend at least $500 on good cover copy and another $500 on sell sheet copy. Dynamite sales copy pays you back many times over.