In his best-selling business book In Search of Excellence, Tom Peters profiles companies such as Hewlett-Packard and United Airlines that practice "Management By Walking Around" (MBWA for short). Management is encouraged to get out of the office and into the field as often as possible to see things firsthand.
Too often, trainers feel constrained by the podium or other setup at the front of the room. They lecture from one spot, and answer questions from the front as well. "Training By Walking Around" means circulating in the room, teaching from various points.
Using a variety of media (computer, white board, easel, etc.) can help get you moving. It also provides variety to hold the attendees' attention.
This is especially important during lab exercises. It's tempting to retreat behind the front desk at such times; after all, you've been standing and talking, and now is your chance to sit, right? Wrong. Try this experiment: during a lab, ask if anyone needs anything. Usually, you'll get no responses. A minute later, casually get up and walk up and down the aisles. Chances are, someone will stop you and ask a question.
I will usually sit for the first five to ten minutes of a lab, then circulate, asking if everyone has gotten started okay. After another five to ten minutes, I'll circulate again, asking if anyone needs "another pair of eyes" to look at an error message. Before the end of the lab, I'll make another pass silently. Usually by then people are stuck on a particular problem and will call me over as I pass by them.
I've even taught from the back of the classroom. I'd been presenting for a while, and could tell the group needed an energizer. So I had them all stand and turn around, and I walked to the back (which was now in front of them.) I did a contest quiz with a prize -- but because they were facing away from their notes and the computers, they couldn't reference them! We laughed about this, the act of standing re-energized the group, and we continued normally afterwards.