After you've found out when a play was performed, you'll want to scan through various periodicals around the date the play was performed to see if a review was published. While we have some periodicals available online (through the 17th and 18th Century Burney Collection, for instance), the search functionality in those databases are not always foolproof. So you may need to search for a publication, find a date shortly after your play was performed, and then open up the publication for that date and skim through to see if you see your performer mentioned.
The process--finding the date a play was performed, choosing a periodical, looking for dates shortly after the performance date, and then reading through the periodical for those dates--is the same whether you're using an online database or microfilm.