Enter the basic plot into an online search engine. The results will often lead you to the film you're trying to remember.
Visit online film databases such as the Internet Movie Database or the All Movie Guide. Type in what you know of the plot and any actors that you remember. Scroll through the results to locate possible film matches.
Call film specialty stores to inquire about your film. The employees might be able to recognize your plot description and give you leads on the title and other information.
Talk with your friends and family about the film to see if anyone else can recall it.