Reviews, and specifically reviews on Amazon will be the single most important thing that will impact your book sales.
What makes one review more valuable than another?
Below are some of the tags that will make reviews more influential on Amazon (you can find them under the reviewers name or on their profile page):
Rather than sit and wait for reviews to happen, we proactively seek out reviews on your behalf.
The reason to run a KDP campaign is to get the AVP (Amazon Verified Purchase) badge . This alone will help insure the review doesn’t disappear and other buyers are more likely to trust an AVP reviewer.