I have written a few movie reviews on Helium and have developed a structure which seems to works. I begin with the film title, year of release and director name. Then I write a short introduction mapping out the review. An effective movie review will begin with a short synopsis of the film, usually no longer than a paragraph in length. This synopsis should give an overview of the plot and main characters. It is also important to discuss minor characters and sub-plots if you are going on to discuss them in your review. If you mention a new character in the conclusion then this will be ineffective and confusing to the reader. It is better to mention everything of value to your review first off.
The main section is obviously the review itself. In order to write an effective review it is helpful to jot down some notes first. The best reviews discus the most important aspects of the film (to the writer). It helps therefore to write down what you think the main themes and motifs of the film are such as globalization, feminism, friendship, loss, politics, etc. The first half of the review should discuss these issues and the relevance of the film to a wider context. How does the film relate to the audience that are watching it? If people are reading the review before they see the film then tell them why the film will mean something to them. The second half of the review should be a more basic summary of your thoughts on the movie. I tend to write a list of the films strengths and weaknesses. Don't forget that you do not have to enjoy a film to write a review. If you do not think that the film was effective in the way it relayed the message of story then say so, but remember to explain why. Talk about the strengths and weaknesses of the basic things that make up a film such as characters, editing, music, lighting and costume.
I always include an extra section to my reviews which I call 'critical acclaim and reaction'. In this section I do a bit of research to assess other peoples opinions. An effective reveiw will discuss the hot topics surrounding the film. Try searching news pages online for other film critics. I think a good review on Helium will pool together sources and information from across the internet to make one comprehensive review. Remember to fence everything you use and include a list of sources at the bottom of the review. This section is not about plagiarising someone else's ideas, it is about discussing and comparing other peoples opinions to your own. It will place your review in context and make it more effective.