Be Physically and Vocally Comfortable, Stay That Way Throughout Your Presentation.
Being physically comfortable will make you vocally comfortable. Often when it's time to give your speech or presentation, you stiffen up. Your shoulders go up, your chest tightens and you've stopped breathing. Recipe for disaster!
Give yourself a good shake! Shake your shoulders, do some vocal/mouth warm ups, pretend to swing a golf club or do a little dance. Anything to relax and get your breathing easily again. Thenremember your connectionto your presentaion. Remember why this is so personal to you. Create a trigger word for yourself that you can write down on the top of every page or note card. A trigger word that you can say to yourself in order to snap out of your 'uncomfortable' self and back to your purpose. This will calm your nerves and release your tension. You'll be able to breathe easily once again. Each page of your presentation can have a different word based on what your talking about at that time.
As an actress I can tell you many stories of cell phones ringing, fire alarms going off and people talking in the middle of a crucial scene while I am on stage. What do I do? How do I keep my focus? I look into the eyes of my acting partner, I look at he scenery or my clothes. I try to root myself into the world I'm in and not the distracting one of cell phones. I bring myself back to my purpose. Then I can breathe easy again.