Breathe Breathe Breathe
No matter who I am working with or what their level of public speaking experience is, the first thing we always handle is breath. The most basic of human functions and yet somehow, as soon as we get in front of a crowd we completely forget how to do it. We start breathing just to survive and not to fuel our strong voice and our power. The breath starts coming shallow into the chest, creating tension in the shoulders and locking up your entire upper body.
The secret to getting past this is to focus on how deep you are breathing. Are you filling up and puffing out your chest as your shoulders raise? This is how 95% of people I work with for the first time breathe when they get in front of a crowd, then when they get to sit down their breath settles back down deep into the stomach where it belongs. This deep stomach breath is where our bodies naturally breathe into when they are free of tension and this is where each breath must go to when speaking to a large group of people.
A good way to test yourself on this is to stand in front of a mirror and take a deep breath. The goal is to breathe as deeply as possible down into your pelvis, and not have your shoulders raise at all as your stomach expands as wide as it can get. This can be tricky and take some practice, but once you master the art of the tension-free deep breath, it will feed your voice with power you didn't know you had, and blow your audience away.