Make sure you have all of the information at hand. You may need to get hold of the book that you used or find an online copy of the text in order to find the specific data. The relevant information can usually be found at the front of the book, on the front cover and in the first few pages at the beginning of the book.
Write out the information, checking it off as you go. You will need to cite the playwright's name and the title of the play. In many cases you will be using an edited version so name the editor(s) and edition. You will also need to note the publisher, the place where your copy was published and the year of publication.
Order the data appropriately. For the Chicago referencing style the playwright's name appears first with the surname preceding the first names and separated by a comma. The Harvard referencing style, on the other hand, requires only the surname and the first initials of the author. The title of the play must be presented in italics in every case and the place in which the text was published and the name of the publisher need to be separated by a colon.