Do reviews sell books? I'm sure they do not sell as many books as word-of-mouth—a friend's recommendation—but they are more effective than advertising. Book reviews are just one of those things an author has to do to spread the word, and if you are publishing your book independently, few if any media outlets—The New York Times, The New York Review of Books, national magazines etc.—will review your book as a matter of economics and principle. It is, I suspect, just too expensive to try to identify the single jewel in the mountain of self-published pulp that is published every day. So what are we self-published authors to do?
You can pay for a review. A Kirkus Indie reviewer will evaluate your book for $425. You cannot control the review, and if you don't like what it says you can refuse to have it printed in the publication. A former Kirkus reviewer writing in Poets & Writers said that about three quarters of the authors she reviewed elected not to publish.
You can pay a service to contact reviewers for you. Word Slinger Publicity, for example, will "create a book review request, the single most important press
release for authors, with our custom HTML template and your book
information." Once you approve the release, "we send out your targeted press release to thousands of book reviewers using our own lists and in your genre." All this and more for $150.
Or you can invest time instead of money. Publishers Weekly's booklife now accepts free submissions. However, the website cautions that while "we want to give your book its best chance for a review. . . we can’t review every book that’s submitted." Nevertheless, I believe it's worth the cost of a couple books and postage for the possibility of a review.
Simon Royle maintains an exceptionally useful website, The Indie View, a compilation of 275 reviewers who review independently-published books. These reviewers do not charge for their reviews (or they're thrown off the list), and the listings indicate what exactly the individual reviewers want to see: i.e., "All except non-fiction and erotic fiction;" "non-fiction sports books;" "mostly chick lit-ish and romantic comedy books;" "paranormal romance/urban fantasy," and more and more and more.
As an author, I looked at the websites of all reviewers who seem interested in my genre and followed their instructions for consideration exactly. Start with a query letter that includes a synopsis of the book, a brief bio, and where the book is available. You have to be prepared to send a .mobi file (the Kindle system), or a PDF, or the book itself—it depends on the reviewer. Some want to know your Goodreads address, some are backed up and not currently accepting books, others are backed up but will allow your book to get in line.
Sending a query of course does not guarantee that a reviewer will want to see your book. That a reviewer sees your book of course does not guarantee a review will follow. And of course, you have no control over a reviewer's opinion. (Although, interestingly, many of the reviewers I approached say they will simply not finish a book or post a review if they find it offensive or badly written or edited or all three.)
All this takes time. It is worth it? I have to believe it is or I wouldn't do it. Will it sell books? Who knows? Certainly a positive review cannot hurt.