Microphones. If there's a podium mic, get used to staying at the podium. Otherwise, you will not be heard! If you have a lapel mic, be aware of where the screen is--you want the lapel mic to be on the same side as the screen, so that if you turn your head to look at the screen, people can still hear you.
Podiums. Don't clutch the podium! Practice with a podium and get used to it. Act normal. If your mic prevents you from strutting across the stage, you can move a little bit around the podium, as long as you're still picked up by the mic. Practice speaking with out the podium and then practice standing behind it. Review TED talks for examples of people using the podium to their advantage.
Panels/tables. If you're sitting onstage at a table while someone else is presenting, don't look like a deer caught in headlights. You don't want to distract from the presenter. Look completely engrossed in whoever's presenting, laugh at the jakes (in a natural way), act like you've never heard the presentation before. When you're at the the table there should be NO audience eye contact--look at the presenter.
Lighting. If you have a spotlight on you, make sure you stay in the light. Believe it or not, sometimes moving out of the light confuses the audience and something in their brain can make them think they can't hear you (even if you're mic'd)!