If there is no template, or if you are writing a book review you will try to sell, there are places that offer free book review template advice.
It is important to note that a book review is very different from a book report. Though I have read some reviews of books and other media that contain spoilers and give away endings, unless requested or noted in the beginning of the review, it is best to avoid giving away the ending or revealing the entire plot line in a book review.
Below I have linked to a few places with templates and advice for writing book reviews. Please review them and use the one you like best, or create your own from the information you find:
Writing with Writers offers a step-by-step approach from an experienced book reviewer.
Tips for writing a book review - From Los Angeles Valley College Library
Book review structure guide from University of Washington at Tacoma
The OWL at Purdue guide for writing a book review
Quick Tips from Writing-world.com for how to write a book review
Suggested elements to be included in a book review
10 Step Process for Writing a Book Review
About.com Classic Literature Guide's steps for writing a literary review
Writing a book review with SEO in mind
For more information and ideas, read some book reviews online and in print. Use the ones you like best as your template for how to format a review and what to cover.
Online book reviews from Bookreporter.com
New York Times Book Reviews
Finally, I cannot remember or locate where I got the information or from what sources I compiled it, but the template I personally use is shown below.
Book Review Template Used by Daniella Nicole
Body of the Review
Rating/impression and why
Have a template you prefer or would like to share? Please tell us about it in the comment section.