Here are some more points to cover when writing book reviews.
Good or Bad
There are always reasons why someone thinks a book is good or bad so think about those reasons and be prepared to articulate them in writing. Some people don't realize that you can't just say a book is good and expect people to accept that opinion.
Any judgment you make about a book must be supported by some aspect of the book. Did the characters make it good? Did they seem like real people? Were they believable? Was it the plot? Maybe the breakneck pace of the novel had you turning pages into the wee hours of the night?
Good or bad, be prepared to support your opinion. However, don't make a review personal, for example, don't call the author names if you deem the book "bad" for whatever reason. Mud slinging isn't what pros do. No writer sets out to write a bad book. Be objective and professional in your reviews.
Strive for professionalism in your book reviews because, one of these days, you may be on the receiving end of a review. The rule of karma usually applies.