As Azvareth said, it's all about practice. When I was a freshman I was incredibly shy and couldn't stand to be in front of people. Then I joined my schools drama and debate team. From there I performed in front of 1-2 people at a time, and as I got better and more confident and made it further in competitions that 1-2 turned to 3-4, then 5-6, to even a packed full room at times. It really helped ease me into confidence. I even performed in my schools musicals and plays junior and senior year.