Don't be nervous, it's fun! Focus on being as overly peppy as you can. You may think you're smiling and look happy, but a normal smile doesn't really come across as happy when you're yelling, so you really have to exaggerate it. Raising your eyebrows helps too. If you mess up, keep your smile and just keep going, if you're really lost try to casually look around you to figure out where you should be. Focusing on a kid is a good idea but if you're in front of the student section where there are no kids, look kind of up and through them and don't be intimidated by them. Our student section used to throw stuff at us, they're pretty awful, so trust me when I say there's nothing to be afraid of! They can't hurt you and they probably aren't paying enough attention to you to make fun of you or even notice if you mess up!