There's a frustrating circle most self-published or Indie authors have to go through. Readers rely on reviews to judge whether to buy their books, but readers have to buy their books before they can leave a review. For most, it's a matter of hoping some random customer will take pity on them and write down his thoughts after finishing your book. One of the problems with this method is that most of the bigger indie advertisement companies only accept ads from books with ten or more reviews. Getting to that magic number can be difficult, but there are things you can do to increase your odds.
If you've already published a book or two, you may have been smart enough to set up a mailing list linked to your books. If not, do that right now; you're missing out on help for your work. People who sign up for your list have a vested interest in reading more of your work. Offer these fans ARCs (Advance Reader Copies) of your newest book in return for a promise to publish an honest review once the book goes live. Make the same offer to friends who like your work. It's unethical to ask for a good review, but if they generally like your work the odds are good you'll get four or five star rating anyway.
There are thousands of people online who publish influential book blogs with tons of avid readers. These book reviewers will read your book and place a review on their site, as well as pasting the same review on Amazon. Before asking a reviewer to read your book, find out some details about her reviewing process.
Does he/she work in your genre?
Does he/she have time to do any reviews right now?
How long does the process usually take?
Do you like the majority of the reviews on his/her site?
Do other writers recommend him/her?
The way to find book review sites is broken down into two categories: free and slowly or paid and easier. If you're working on a shoestring budget, you'll have to do all the legwork yourself. Do a search for book reviews in your genre and start reading book blogs that contain reviews. Email each blog owner individually and ask if he's accepting books for review. Keep doing this until you have a dozen or so blogs willing to review your book. If you've got some cash to invest, on the other hand, you can hire a company to set up a book review tour. This will put your book in front of a pre-determined number of reviewers with no more work from yourself than pushing the PayPal button.
Once you've found a list of reviewers, wait a couple of weeks after you send the book. Follow up with a quick email if you haven't seen or heard anything by then. Not all reviewers will be willing to review all books. When a review does arrive, make a point of sending a nice thank-you email to the reviewer, to show your appreciation for taking the time to work with you on your book marketing.
Keep the Faith and may the Force be with you!