There are many different ways to search for film reviews online. Here are some good tips.
1 What year did the film come out? This will be key to discovering reviews. If you don't know the year, check the IMDB (Internet Movie Database)- there are usually some reviews available there as well. Look on the left hand side of the screen under External Reviews.
If you are looking for reviews before 1980 or so, it is harder to find online reviews. However there are some good sources
Check the New York Times Historical Archive - follow the tips below:
The same hints work with the current newspapers and magazines including the New York Times - also searchable from ProQuest.
You can also find reviews in the newspapers and magazines covered by Lexis-Nexis Academic