First, do NOT solicit friends, family, or fellow authors to write those reviews. That is explicitly against Amazon's terms of service and is also considered unethical. Reviews should always be unbiased statements by "uninterested parties." Review swaps are also disallowed for this same reason, as are paid-for reviews. Amazon - and buyers - want to see wholly authentic reviews by people who have no stake at all in the book's success or failure.
Your first step in getting those reviews is to write a killer query letter. This is what you'll be sending out to elicit reviews. Make sure it's about a page long and describes why the book is interesting to read. Avoid making the letter about you or your background unless it's critically important to the book's foundation. A person who's run a gardening store for thirty years should mention that when hawking a book on gardening techniques. A person who's a first time writer who struggled for thirty years to write this tome should leave that out. The focus needs to be on the book and why the reviewer will love reading it. That's what the reviewer cares about. As they typically get swamped with 50 or more requests a day, you need to make the case that your book is the one worth spending time on.
Look through the top 500 Amazon reviewers to see which have reviewed books in your genre before. It's not worth your time (or theirs) to send notes on a mystery book to a person who only reviews sauna equipment. Email each one personally. Next, look at the top-rated reviews on other books in your genre. Contact those reviewers and ask them to take a look at yours.
Search out every blog you can that writes about your genre. From small to large, if they post about your genre, send them the letter. Always personalize your letter to them. Don't forget local papers. Talk with every local paper about your new release and ask them about getting a review or interview.
Never send the actual ebook unannounced. Many people use their phones to read email and that large file can gobble up their download speed and monthly limit. Always make the OFFER in the query letter but leave it to them to choose any format they wish, including paperback if available. The review copy should always be wholly free. Note you cannot have them buy it and then "pay them back." That is against most sales sites' terms of service. You're now considered to be paying them to write the review.
Make sure your book itself, immediately after the story ends, has a direct link to Amazon's review page for your book. That way someone who finishes your story has a one-click ability to leave a review. For your versions on other platforms customize them in the same way. The easier you make it for that review to be left, the more likely it is someone will do it. Readers are more likely to do that right after reading, when it's fresh, vs later on when they have moved on to something else.
Finally, market, market, market. The more readers you get, the more authentic reviews will get, which will get you more readers. It all snowballs!
Sending Out Review Copies
Common Mistakes when Seeking Reviews
Review Swapping - Why to Avoid It
One Star Reviews
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