If you are presenting in a location where you can impact the lights, you should take advantage of this. It can really brighten up your presentation. Get yourself in a nice spotlight in front of your audience.
Use accent colours on the background that match the atmosphere that you want to create with your presentation.
Vary the intensity of the light. For example when your audience need to speak up, have more light in the room that lights up the audience. When there is a video to be shown, turn off the lights in the room.
When you have the lights set-up on a stage try before where you can stand. Have someone in the room check if there are no strange shadows on your face / body that look unflattering.
You could mark the places where you can stand on the floor of the stage with a piece of white tape, so you these places are easy to find when you are on stage.