So. I get really nervous when public speaking so I have a few tips that sometimes help me. Hope they help.
My first tip is to know your material because when you don't you worry and panic
Secondly, don't stare at people, try to stare at the back wall because it's easier to think that you're by yourself.
Depending on what you do when your nervous, I usually laugh or chase and stutter. When I laugh I try to act happy the whole time or think of something depressing. When I stutter or shake I try and play it into the speech (like in my I am David monologue)
Sometimes I just stare at a light before hand when I'm up just thinking how it works, it keeps my mind off of the speak.
Breathe deeply when up on stage
Don't look at friends because sometimes just looking at them will make you laugh
Hope it helps and sorry it's short