I found this site while trying to help a friend promote his book for Amazon: http://reviews-easy.com/ It's a big database where you can find the highest rated reviewers on Amazon (of course for many domains, but you can find also book reviewers). From what I've seen on similar sites this type of service is quite expensive (on this site it's for free), to find professional reviewers to endorse your work, but seems somehow necessary when you are not a social media guru, no one has heard of you and has no good reason to buy your book
![Smile :-)](https://www.booktalk.org/images/smilies/icon_smile.gif)
Have you ever tried tried something like this?