Unfortunately, it has become a common practice to review a book without reading it properly. The reviewers just go through once and draft their review without having proper understanding of the subject. You should read the book thoroughly. Do not stay on the surface rather try to read between the lines.
If you still have some confusion then you should consult some knowledgeable friend. Be honest and do not pass a judgment without solid knowledge. You may even contact the author of the book and ask him all the questions. This will really help you to understand his point of view and you will be able to write a perfect book review.
It is better to do some research about the writer. You should know which school of thought the author belongs to. What he has contributed earlier and what was the reaction of other critics.
Prepare a complete thesis before writing your review. Make note where you disagree with the author and where you think that his/her approach is right. Evaluate the story and write down its strengths and weaknesses.
Now, when you are done with all the research work, it is time to start writing your review. You should divide your analysis in different parts such as beginning, main body, final paragraph and the summary.
Start with a catchy sentence and lock the attention of the reader. If you are impressed by the book then give everybody a shock with a bluffing statement. You can stick with the standard pattern of introduction in which you give the name of the author, title/subject of the book, publisher etc.
After giving introduction, you should present your analysis. Do not play with words rather you should be to the point.
Summarise your review in the last paragraph and then mention your full name along with contact information.