Once you've identified a database to search:
1. Search for the film title in quotes. Make sure you are putting quotation marks around the title to ensure the database is search for the words together as one unit.

Other keywords you might try include the last names of the leading roles or the director.
2. Make sure you are paying attention to the date on reviews.

Sometimes older movies will have more contemporary reviews as they get re-released into newer formats. You can often find the date under the title of the search result.
3. Explore either the advanced search options or the filters to the left of your search results for ways to manipulate the publication date of your search.

Changing the date range of the results to be the year or two years surrounding when the film was released will help ensure that the results are relevant. If you change the dates to the date matching your film's theatrical release and no results come up, then the database you are searching might not have a review for your film and you'll want to check a different database.