There are several review sites online that you can write a review fas a freelance writer. You can pick and choose what you'd like to write your review on. If you'd like to write only book reviews then you might like to check out:
- Social Spark
- Review Stream
- Sponsered Reviews
Each one of these sites allows you to compose and submit a review for consideration. Any site that accepts freelance writers will always review your work before posting it on their site and paying you for your review.;
Actually, the best way to write reviews about books is on your own blog site. You can make deals with the authors of the books to review their book and post the review on your website or blog. If you review generates a sale for the author you can earn a commission.