I don't know if there is such a thing as a "perfect" movie review.
When I sit down to write a film review, I try to communicate as honestly and as straight forward as I possibly can how I responded to a film, and why I responded to it the way that I did. That's really all you can hope to do when you write a movie review. Maybe you saw meaning in a film that many overlooked. Write what you got out of it and how you interpreted it the way that you did. Maybe there is a movie everyone loves that you hate, and you want to make an argument about it. Write what is was about that film that you responded to so negatively.
Provide a synopsis of the plot so that readers will know something more about the film you're writing about. Talk about scenes in the film that stand out. More than anything, just be honest about how the movie made you feel. You have your own individual point of view; express it as well as you possibly can, and it will stand out.