There's a little story to this but it really puts it in context.
I'm in university and we were putting on a play to celebrate a festival. I was asked to do a bit of comedy for the play and I gotta tell you guys I was terrified on the night. It's different going before a huge crowd of people (there were people sitting on the floor of the place we had the play). It's amazing how freaked out you can get.
My friend who is a natural pulled me over and told me something he learned from doing years of yoga.
He said: Relax and recognise your breathing...it's shallow and faster than usual...slow it down...breathe in and out deeply and slow it down...be conscious of your breathing throughout your scene and you'll be fine."
Well I did as he said and everyone in the university knows who I am now because they loved my scene. Naturally I decided to apply it to approaching and it's amazing how calmer I feel. I love it. He told me that he uses it whenever he feels nervous and such. It's root is in yoga but it's been used in nlp.
So just relax...slow down your breathing and be aware of it as you approach

it's awesome and I home it works for you guys as well as it did and does for me
