What are sock puppets? Well, when you're talking about books and ratings and reviews, sock puppets are wool-headed people, whose mouths only move when you tell them to, and who never say anything except what you want to hear. They fall into two classes: (1) people who offer to write a glowing review (or 25) for the one-time "small fee" of . . . . whatever they think you might be willing to pay; and (2) your mother, your first-grade teacher, your best friends, and your writing buddies, all of whom think you walk on water and can hardly wait to tell the world that yours is the best book ever written.
Ugh. Of course you know better than to purchase paid reviews from an internet site, where the reviewer will probably never lay eyes on your book. But you also need to avoid your family and friends, who will be afraid to give you an honest assessment. Very few books deserve 5-star ratings. Most writers are just not that good. I know I'm not. I can design a plot that works, I have a fair ear for conversation, and years of teaching have taught me to understand people. But my books are not earth-shaking. They don't contain profound truths or lyrical language. They are, at best, good reads, and perhaps once in a while someone learns something from them. But if I were rating them, I'd be passing out the 4-stars and 3-stars. And when reviewers give them similar ratings, I'm pleased. An honest rating should draw the kinds of readers I want. Those writers who fudge their ratings or complain about anything less than five stars are kidding themselves, and in the long run, readers will recognize that, as well.
Now, it's true that book sales depend on ratings, but you can do several things to get honest reviews. Ask for them in the internet. Strangers do volunteer, and while you may get a troll or two, their nasty attacks are usually clearly identifiable. Here's another place to look for reviewers:
The people on Amazon's reviewer list are readers who love books. They list the genres they like and provide an e-mail list for contact. Write to suitable reviewers and ask them to read your book. You'll get an honest assessment from a knowledgeable reader who knows what goes into writing a book. And Amazon will be eager to promote you if their own reviewers say your book is good.