That can work too!
I have from 2-4 presentations a year. My trick is just to act like i'm awesome and know everything! It also helps if you have a friend in the class. For BioChem last year i had to pick a disease or disorder. I picked hemophilia, because my character Pip has it and i've done SOOOOOO much research on it just for my books, I considered myself a pretty good expert on the topic.
I told my friend about my character and why i knew so much. She laughed her ass off, especially when i went up there and talked about "my friend John" (aka Pip who i made up) who had Factor 8 type A hemophilia. heheheheheh. My friend was in the back of the room giggling as I shocked the class with pictures of swollen elbows and talked about "John"
I stopped being scared of presentations when i realized that the only person actually listening to me when i stand up there and speak is the teacher.