Body control is the name of the game when you are speaking before an audience. You do not want to stand before an audience and be fidgeting with your hair, wringing your fingers, or tapping your feet. Why?
Because this does not portray confidence! It does not show that you are in charge and that you have things under control. As a public speaker—you may get nervous—but your audience never has to know.
As you grow in your public speaking, you will need to be deliberate about your movements and gestures. You want to make sure that each move will enhance your presentation. If it will not then you do not need to make the move.
I know this is easier said then done—because sometimes you may not be aware of your movements—but you should be. How can you be aware of what you do on a subconscious level? Observe yourself or have someone observe you.