For me, I preach each Sunday. Before I ever get up on the stage on Sundays I rehearse messages out loud in my office. I seek to prepare for things beyond my control such as sound system feedback, a baby in the audience crying, people getting up out of their seat to go to the restroom, and many other factors. All these things have happened while I've been preaching/teaching at my church.
Whatever you find yourself doing, seek to "stage a simulation" before actually doing it. You'll find in the moment when obstacles arise in the live event you're prepared. You will silently say to yourself, "I was expecting that," and then move with confidence.