A good tip is to sound loud, Ik that a bit hard to do when you are a shy person. I use to be nerves to do presentation but Sounding loud and clear will help.
Another this try not to feel so tense give you self the wiggles if possible and breathe in and out and tell your self you got this, and you are only doing it ones this will tell your brain that you have it control.
Don’t be scared Ik it scary at first but later on in life you are going to do more like this. You are going to amazing:)