Basically, patience, and offering your book to interested people in the hopes that they will both read and enjoy it, and comment in public upon it.
You could offer free promo copies to a select audience which you think might be your best-targeted reading demographic in exchange for an honest review, as long as you're willing to live up to that no matter what comes out and the reviewer discloses that they got it free in the review in exchange for said review. I've seen a couple of reviews like that where people got stuff via LibraryThing or other giveaway and say as much, and they tend to be fairly thoughtful, coming from people who are dedicated about their reading.
But basically, it's really a waiting game because there's no guarantee that people who accept review copies will even get around to reading your book*, much less that they'll like it when they do.
And to be honest, the disproportionate responses of a number of authors behaving badly has tended to put people off doing reviews for unknown writers in a lot of venues, just in case there's the chance that the writer you give a overall positive and mostly praise-filled 3 star for "good effort, minor issues and could use a little more polish, but overall really liked the story and would like to see a sequel" will turn out to be a lurking psychopath bent on flaming you to death for giving an insufficiently stellar† review.
And with that I link this helpful Saturday Morning Breakfast Cereal cartoon:
How to Communicate With Writers
Good luck with it!
* I often don't get around to reading my actual paid purchases within the same year I bought them, much less non-urgent freebies by people I've never otherwise heard of.
† Which I personally seen happen a couple of times, with at least one author asking her friends to downvote the review on Amazon, then making threads to mock the reviewer's statements in several public fora, and changing her book's description to include said mockery, and then pretending not to know about a flamewar that one of her fangirls was holding in the comments of the review while at the same time being gleeful on Facebook that the "controversy in the comments" was driving up her sales.
And that was for a positive 3-star review. For a mere 2 stars, apparently you can get called "a rat and a big snake" on your very own blog.