Have you ever read a movie or book review? Was there too much of the plot in the review that you did not need to see the movie or read the book? That is why when writing a review, one has to have a very concise description of the subject. I was on the newspaper staff in high school and I had to write my share of movie reviews. The reviews that ran in the paper had a very brief summary of the plot and a majority of the review was how I liked it and what could be improved.
When writing evaluations one should write for the age group the movie is trying to target. If the target age group is teens, use language and act like you are talking to a teen. Also, more people will read a review is written by someone in the target age group. For example: I wrote a review on the movie "17 Again," and more people read it because it is a teen movie and the review was written by a teen.