I plan to rate my reviews on a standard 5-point scale, with 1/5 corresponding to an F and 5/5 corresponding to a new addiction. I the book on 5 scales, Plot, Characters, Setting, Writing Style, and Potential. I grade each scale 1-5 and then take the mean of all the scores to get the total.
Here is an overview of my criteria for a review:
This is the overall story, and what developments in the novel lead to the protagonist taking action. I enjoy plots that have twists and turns, never allowing the reader to accurately predict what will come next. At the same time, the plot must make sense within it's own context. If I am reading a teen romance set on the rooftops of New York and the climax is a dragon terrorizing the city, it is difficult to put 2 and 2 together.
These are the people who make up the story, and what their personalities and characteristics are. I look for dynamic characters, who change throughout the story. Otherwise, the character's action become too predictable. An example of a dynamic character: A suicidal man who learns to embrace life.
I also look for well-rounded characters, who have multiple aspects to their life and personality, and have strengths as well as weaknesses. Well-rounded character: Cheerleader who suffers from an eating disorder, but volunteers at an old folks home because she wants community service hours for college, because she fears her cheerleading isn't enough. The opposite of this, is a cardboard character, one who only has one distinct quality or is a stereotype. An example: A jock that likes to give wedgies. I would much rather have: Jacques, a potato wedge salesman who seeks a new sour cream recipe.
This is the where and when of the book. Does it take place in a Kentucky barn in 1856? How about a jail in Victorian London? Now, most books will bring the characters to many destinations, but the broad scope of where they move around, is the setting.
All authors have a unique voice in the way that they tell their tales. I like to take into account, how their style affects the book. Now novels can either be written in first-person, second-person or third-person point of view. The choice of which to use, will often determine how successful the story is told. Also, whether the story is told in past-tense, present-tense, or future tense (?) will determine how successful the story is told.
Another factor is pacing. Pacing is how the action is spread out in the story. This is more related to plot, but authors tend to keep a consistent pacing in their works. I look for books where the pacing keeps the story moving along, where plot developments occur often to hold the reader's interest. I would not like a book where the first 20 pages involve the protagonist doing yard work, if that does not move the plot forward. If the plot is a treasure hunt, and the protagonist is leading a dig in his backyard, than that is shoving the story in motion.
Within this category, I also include description. How well does the author convey what the world is like? Some authors choose to be very brief in describing their worlds, while authors will ramble on for days on every detail. Either is fine, just as long as the description brings the story to life, or at least allows the reader to picture what's happening in her mind.
Not all authors hit the mark on their first try, but that doesn't mean they are not worth following up on. Potential is how likely it is that the book will spawn a sequel, be turned in to a film, or how likely it is the author will find success in the future. Potential can also be how likely it is that I will reread the book in the future, or if I am going to recommend it to a friend.