So, I figured it was time for an actual writing post.
I'm going to talk about reviews. Reviews have become more and more important (for example, many promotion sites won't promote, even for pay, self published books with less than X number of reviews) as the industry changes.
There are three kinds of reviews:
1. Paid reviews. Meaning...you paid somebody to review your book.
Don't do this.
It is majorly unethical and if you're found out both you and the reviewer will be ostracized. Amazon will remove reviews that were paid for if it finds them.
Note, this does not include paying a service like Netgalley to find you reviewers. And it is industry standard to provide the reviewer with a free copy. That's perfectly acceptable.
2. Customer reviews.
Customer reviews are spontaneously posted by people who bought and read your book. Awesome, right?
There's no way to reliably get more customer reviews - calls to action may or may not work and can look unprofessional. Statistically, about 1% of your customers will bother to write a review. A slightly larger number will give a straight star rating on a site like Amazon or Goodreads. (Be aware that Goodreads star ratings can be a little misleading because some people use them to prioritize the books on their to be read list...)
And, obviously, customer reviews can include some really problematic stuff. There's the risk of receiving what I call an "ugly" review, where they're reviewing the author's perceived politics, etc. Or, of course, a good friend posting a five star review to be helpful (This is not always because the author is asking people to shill for them).
Customer reviews are both more and less honest than the last category:
3. Professional reviews.
Okay. This sounds like people being paid to be reviewers, and it does include them. However, a professional reviewer in this context is anyone who solicits books for review and reviews them regularly. In the internet age, the vast majority of "professional" reviewers are bloggers with more time than money doing it as much to support a book habit as anything else.
These are the reviews you can actually set out to get, although it's still hit and miss. Most book bloggers get more books than it's humanly possible to read, and I've found the ratio of actual reviews to solicits is pretty low.
You can find reviewers on the internet. The Indie View has a good list. Net Galley puts you together with "semi professional" reviewers - those are people who sign up for the site to get free books, but it's expensive for the author (best to go in with a cooperative if you can find one). There are some other services which are cheaper, but less well reputed.
Read the reviewer's blog. Read a few of their reviews before sending in your book - you might, for example, not want to send your book to somebody who has reviews posted in which they attack the author or go for extreme snark at the expense of the poor book.
Read their guidelines. Only send to reviewers that read your genre and subgenre. You should write a query letter which states why you're sending the book to that particular reviewer - it's not always possible to come up with a personalized reason, but you'll have a much greater chance of success if you do.
If you're working with a publisher, talk to them. You don't want to send the same book to the same reviewer.
Oh, and don't worry about reviews. Ultimately, you have very little control over them - and while it can be frustrating when "not enough reviews" blocks off marketing opportunities, it's even more frustrating to obsess over it.