I got my under-grad degree as an adult and most adult programs are built around group projects and presentations...so I can TOTALLY relate...
I found that being 110% prepared is the only thing that alleviated my fears. If I wasn't completely prepared and VERY familiar with the material I was a mess...
On a side note - I'm fairly new in my current position, 9 months, and when I took the job there was NO mention of presentations and training...well, imagine my surprise when it turned out to be 35+ % of my responsibilities.
Again, what makes me comfortable is being very familiar with the subject matter and also knowing that I am the expert on my subject, NOT the audience, and they are there to learn from ME......that gives me the boost of confidence I need to be calm..
I have found that after the first couple of minutes of sheer terror, I usually get into the groove and things are fine
One of my teachers taught us some breathing techniques to help calm ourselves that I use sometimes...he also suggested that you get to the room BEFORE the presentation and get comfortable with your surroundings...stand up front, then walk to where your audience will be sitting and back....I do that too when I travel to our other locations to present/train...
Good luck!!!
P.S. If you're in a school presentation sitch, remember, EVERYONE else is nervous about their presentations too...so chances are they aren't even listening to you!!!
P.P.S. Another trick I used at school is to volunteer to present FIRST that way you don't have time to get yourself all worked up!