I used to be nervous about presentations but accidentally cured that in my second year of uni. Had to make a website with a few basic pages and one on a "Scientific Interest" that could be "anything you like as long as you can reference it" and it was a really silly module anyway so I decided to have fun with it. Took the mickey completely and wrote a rather odd page for my scientific interest, all about how the fictional animal called a tribble reproduces. It was fun
We had to do a presentation on our websites and for once I looked forward to it. I knew I'd done something insane, I knew the reactions I'd get and I wanted to have fun with it. I took in some tribbles, threw one around the room when it purred and vibrated when hit/thrown... Thoroughly enjoyed the startled reactions and made sure no-one forgot it lol
I even had friends wishing they could be there, and the best thing of the lot - I got decent marks and a comment on the good use of props
After that presentations never bothered me so much