Between grad school (teaching, seminar talks, etc) and other occasions, I've spoken in front of groups of 3-300 people hundreds of times. I have no idea if I'm all that good at it, but at least I'm comfortable with it. :-)
The biggest trick for me is realizing that talking in front of a group is different from talking to one person, but talking in front of a small group is not that different from talking in front of a medium or large group. Under 5 or so people is still pretty much an intimate/conversational atmosphere in my experience, but going from 5 or 10 up to 50, 100, or 300 is pretty much all the same. The only real difference is the amount and type of projection equipment involved.
Depending on the specific scenario, there are other things I try to keep in mind (e.g. I found that between 0.5 and 1.5 slides per minute worked well for a seminar talk in grad school), but abstracting away the size of the audience in my mind is the one that's paid me the biggest returns in reduced anxiety. Now if I just had a way to make sure the A/V equipment always worked, I could make a crapload of money. ;)
The biggest trick for me is realizing that talking in front of a group is different from talking to one person, but talking in front of a small group is not that different from talking in front of a medium or large group. Under 5 or so people is still pretty much an intimate/conversational atmosphere in my experience, but going from 5 or 10 up to 50, 100, or 300 is pretty much all the same. The only real difference is the amount and type of projection equipment involved.
Depending on the specific scenario, there are other things I try to keep in mind (e.g. I found that between 0.5 and 1.5 slides per minute worked well for a seminar talk in grad school), but abstracting away the size of the audience in my mind is the one that's paid me the biggest returns in reduced anxiety. Now if I just had a way to make sure the A/V equipment always worked, I could make a crapload of money. ;)