I never got that either...like imagine they're all in their underwear or something..I don't know but when I look at my students or audience I see people as they are..meh must be the S in me. The only way I got better was in training for my job we would give presentations every day. Starting around 3 minutes long and the last one was infront of my divisions project specialists along with the rest of the class. So the only way to get better is do it over and over. Something that helps me is that when i'm training I always think that they want information and need this information in order to do their jobs so that makes me feel better.