Go to an online book store and look for editorial or professional reviews (rather than customer reviews):
http://www.amazon.com
http://www.barnesandnoble.com/
Locate reviews out of periodicals using a periodical database:
Locate book reviews from the New York Times back to 1981:
Locate film reviews by the late film critic, Roger Ebert, and from other professional film reviewers on staff at RogerEbert.com:
Locate reviews out of periodicals using a periodical database
Locate film or television reviews out of film periodicals:
Film and Television Literature Index
Locate film reviews from books in the library's collection:
Locate reviews of technology-related products at CNET:
Locate reviews out of periodicals using a periodical database
Helpful guides to citation styles: