Finding reviews of a performance can start with UC Library Search or with a specific article index in TDPS—such as International Index to the Performing Arts (IIPA) and International Bibliography of Theatre and Dance among others. Finding a review of a performance, however, usually also requires access to newspapers or trade publications from a specific place and time. To determine which newspaper database(s) to use, among the many available, consider the context of the performance you're looking for: Do you need reviews from a particular city? Do you need reviews for a contemporary performance or an historical one?
News resources are especially helpful for finding information about contemporary authors and playwrights who are not yet the subjects of scholarly attention. They are also helpful when looking for historical context, interviews, reviews or biographical information.