One of the PE teachers at our school is switching to teach Kindergarten this year. I stopped by to offer some advice:
When you tell the kids to come in the room, tell them to "sneak up on their chairs" and they will enter quietly.
Remember, you are not the teacher, you're just the kid who gets to be in charge.
Try to act extra excited about stuff, like, you know, if you want them to pick up a piece of trash, you can say, "Wow! That is a really cool piece of trash! Who wants to be the one to pick it up?"