Haha...I just had a presentation on monday that I was crazy nervous about. I'm the type of person who works herself up so much I literally get sick to my stomach for days before!
It went very well, though. Some advice...
Nobody cares about your presentation. Seriously. You can have the worst presentation in the history of bad presentations and still nobody will remember the next day...or even a minute later! Nobody cares if you look stupid or sound stupid. When everyone else is doing their presentations, look around the room. Some students will be watching (the keen students who actually want to learn something from you), some will be texting their friends under their desks, some will be sleeping, some will be staring off into space thinking of other things, some will be looking at the presenter nervously anticipating their own presentation.
For my presentation (which was an hour long and in a group of 4), I did the introduction and had a 15 minute break where I just stood and waited for everyone else to say their part. I had nothing else to do but look at the audience. There were no hostile expressions at all. Nobody wanted us to fail...Nobody laughed or even seemed to notice when my group members stuttered or mispronounced a word. Presentations are hard for the majority of people and thus the majority of people know how you feel and want to see you succeed.
Meditation helps a lot. Not eating a few hours before the presentation helps me. Think about waking up on saturday knowing you've done your presentations and don't have to do them again.
Another tip...Know your material well. I always write script and go over it and over it until I've almost memorized it. It makes things easier knowing what you're going to say...Even if you take the notes up with you and read straight off of them. Remember to breathe deeply, doing so tricks your body into thinking you're not nervous and takes away a lot of the nervous symptoms.