T he audience reads your body language as much as they read your slides or listen to your words. Stand whenever possible. Standing gives you an air of authority, it makes your voice project better, and makes it easier for you to gesture. Smile when you first get up to speak, and again whenever appropriate. A smile goes a long way toward making you and your audience comfortable.
People let their guard down and smile back.
I use this technique when I shoot portraits of people that I've just met. Look directly at one person at a time. Keep your feet squarely planted on the floor about a shoulder's width apart. Avoid shifting your weight or rocking back and forth. Don't pace back and forth across the front of the room, stay at the podium.