Going to the theater is an amazing, costly experience and trust me, you don't want to be the person that unintentionally ruins the experience for those around you. Here is a quick list and video of do's and don'ts to follow that will ensure that everyone has the opportunity to enjoy the show.
Do not use your phone or any electronic device during the performance. If you don't want to turn your phone off, putting it in airplane mode will suffice.
Please refrain from talking during the performance unless you are encouraged to do so by the performers.
If you buy snacks prior to the show or during intermission, please open them before the show begins to eliminate noise during the performance.
Please do not take photos or videos during the show.
Lastly, please do not leave during the curtain call unless it is an emergency. This is the time to celebrate the actors/actresses for their hard work during the performance and leaving can be considered rude and hurtful to them.
Please see the video below, posted by Tyler Mount from Playbill.com, with etiquette tips as well. If you would like to skip past his personal experience from Phantom of the Opera, please skip to 0:48.