I've pinned posts to the top of my Facebook author pages asking for you to post a screenshot of your reviews in the comments. See example:
Pretty simple. If you've already left reviews on my books, post those screenshots in the comments. If you haven't reviewed a book yet, now's a great time! You can post a screenshot for every review you do so with all the different books available and all the different places you can leave a review, there's a lot of ways to build up your entry numbers! Each time I finish writing a new book I'll randomly choose someone to send an advanced reading copy to BEFORE THE BOOK RELEASES TO THE PUBLIC! (exception to this would be Kindle Worlds novellas which I would not be able to release to anyone prior to release date due to the fact Amazon would be in control of releasing the book)
This will be an ongoing contest so if you don't win when my next book is completed, don't fret. You'll have a shot at the next one!