Come up with a thesis, a central idea to discuss and back up with your observations on the various elements of the film. Your thesis should be discussed in the first paragraph of your review.
Does the film reflect on a current event or contemporary issue?
Does the film seem to have a message, or does it attempt to elicit a specific response or emotion from the audience? You could discuss whether or not it achieves its own goals.
Does the film connect with you on a personal level?