The body is an extremely loyal and obedient tool of the mind. Whatever you think or imagine, the body does its best to fulfill. It has no other choice. The individual muscles, organs, bones, etc don’t have the capacity to think. They can only move when told to do so.
Many imagine this to only involve physical movement. It applies, however, to the body’s ability to communicate your thoughts.
The human face is the most expressive area of the body. Besides the basic functions of sensory input, the face is built for the purpose of expression. Expressions are created by muscle movements motivated in the mind by thought. The same type of thought that motivates the leg or arm to move.
It is because we execute physical commands so often that we take for granted how abstract the origin of the movement is. All impulses and commands are thoughts, compiled in ways we still don’t understand, from electrical synapses.
What does this mean? It means that onstage your body and face will express what you are thinking. It has no other choice. It’s been trained to obey all commands without question. The body doesn’t know the difference between real and fantasy and it doesn’t care. If you worry about what you look like onstage your face and body will display that worry. If you fear looking silly your body will interpret the image you fear as a command to adopt that posture or look.
You can override your face but it takes the conscious command to not display your thoughts (which ironically displays to everyone that you are closing yourself off). When you stop up your facial expressions your body usually compensates by displaying tension in various areas.
We take a lot of pride in being able to create and use language, which we should because of how amazing and complex language is. Despite this complexity, verbal communication is not the whole story. Most communication is interpreted through context, body language, and facial expression. To be able to communicate effectively each need clear and specific motivations.
The point of it all is to be specific in your thoughts and choices and trust that it is coming across. The more specific the thought is the more muscle groups are activated and the richer the expression becomes both in face and in the body. The audience is watching closely and they are very receptive to every posture, movement and/or expression; their brains are mimicking your actions and eliciting a physiological response.
Stop trying so much and just do!