when you stand on that podium or in front of your class, you WILL be scared no matter what. dont fight your fear. Accept that you will be scared. As your legs start to tremble, as your throat runs dry,as your heart pounds, and your head dizzy......PAUSE......give yourself five seconds and observe yourself getting scared. observe, watch, see  yourself getting scared right there while you are about to freeze with fear.... once you stop fighting fear and start understanding fear, it should go away.....