You'll need blurb and possibly promotional copy for the back cover as well and it should tie in visually with the front. (knockinbooks.com)
If a prospective customer sees that you can't even write a few sentences of compelling, error - free promotional copy, what are they going to think of your book? (bidinotto.com)
Send promotional copies of your book to influential people, like bloggers in your niche or book reviewers. (writerswin.com)