[quote=Cpt Toellner]
Lay down the law, make sure they know who's in charge, never be flexible abound theatre students.
[/quote]

Do literally the exact opposite of this.

Be approachable. Make it easy for the performers to talk to you and ask questions, whether to clarify misunderstandings or help make themselves comfortable around you. Treat yourself as one of the people helping make the production, rather than the authoritarian all-knowing god that presides over everyone else.