Walking onto an empty stage is easy, when there is no one in the audience.
The moment you see someone watching your body changes inside, even if it is just a little change. You tense a little, straighten up a little. You focus on the fact that someone is taking notice of what you're doing.
If it were past tense, it would be less of a problem. Being watched on film can unnerve you the same way, but you can always close your eyes or leave. Separate yourself from the situation, distract yourself from what they are thinking because it already happened and that gives it a distance.
On stage the distance is measurable. And strangely miles are worse than inches. Up close you can be sure of what they see. See their eyes, see their reactions. But from afar you cannot tell where they are looking, just that they are looking.
So you call out. Ask them what they hear.
"Can you hear me?"
Reply or not you have your answer. So you speak up.
"CAN you HEAR me?"
Self expression is all about angles. How light hits a photograph and the objects in it. How a camera catches a figure or movement. How air or force form a note. How people can see or hear through a medium. In self expression, the key is where you are when you do what you do. Whether in the crowd or above or below, millions strong or face to face, it all depends on where you are when you do what you do. And if you do it the right way, you should never have to ask.