General
1) Don't touch other people's props or costumes.
2) Don't give the other actors direction.
3) Always be on time to call, if not earlier.
4) Pay attention to your stage managers when they speak and then do as they say.
5) Don't eat/smoke/drink in costume.
6) Remain quiet at all times while you are in the space (green room, dressing room, backstage, etc.).
7) Stay involved with the show as it progresses and try to stay in earshot of the action.
8) Look out for one another, both on and off the set. Injuries suck, and so does missing a cue.
9) Remember to be courteous to your director both during and after rehearsal and performance. No one likes to be treated with disrespect, and everyone enjoys a pleasant greeting and a kind word.
Headset
1) When you get on headset, announce your presence.
2) When you get off headset, announce your absence.
3) Always get permission from your stage manager before going off headset.
4) Acknowledge your warnings and standbys.
5) Unless you're the stage manager, put your headset in the mode that transmits only when you press the button to talk, rather than the continuous transmission mode.
6) Dissuade actors from yelling into the headset microphone.
7) Do not distract the stage manager from calling the show.
8) Do not talk during standby.
9) Respectfully stop talking any time a stage manager requests silence.
10) Above all, respect your stage manager and each other.