Calm public speaking nerves by "scouting the territory"

There are many things you can do before your speech to calm nerves. Obviously being prepared is one, and another is a set of things that make up a routine to go through beforehand.

Before you make your presentation, if at all possible, arrive at the venue early and make it your own. Walk the walk you will make to the stage or lectern. Walk around the room and make yourself comfortable with your surroundings. Feel comfortable with those surroundings ... feel confident walking, standing, looking.

When you come back to actually present, that feeling should still be there and you can harness and use it to present with confidence.