Anticipate your audience. If your audience is at a school or consists of children, you may need to spend time reminding them to sit quietly and hold their applause until the end of a scene. Adults will not need this type of information.
Write out note cards, using a pen, to state what you will say in your introduction. For example, if you will be reminding the audience to be considerate, make a list of activities that are not appropriate during the performance. You may also want to jot down some notes providing background information about the play.
Rehearse your speech until you can say it flawlessly without note cards. If necessary, practice it in front of friends and ask for feedback. Make sure your speech is well modulated and clear. When the play is introduced, make sure your demeanor is appropriate for the audience and the play. Usually you will want to introduce the play enthusiastically and build up the excitement of the performance. Sometimes an introduction may be somber if the subject matter of the play calls for a more serious tone.
Check with the play director to make sure there are no last-minute cast substitutions. If there are a lot of substitutions, you may wish to jot them on a note card, but the rest of your speech should be sufficiently rehearsed so you don't need to read it.
Check the acoustics at the theater. Test the microphone and make sure it is easy to use and your words can be heard.
Introduce the play a few minutes before the production starts. At the end of your introduction, remind your audience to enjoy the performance.