I teach Spanish and float to elem classes each day on a rotating basis.
1) One phrase I use is [Me]: "I'm talking" [Them]: "i'm Listening"
2) Another thing I use in elem classes is I have a little bean bag juggling ball that I pull out alot. If I have the ball, I am the one who gets to talk. I toss the ball to students one at a time and they get to answer a question or tell about something (you know how they all have stories to tell lol) I have small classes in lower elem, so that is something that works for me.
3) Something I have used in children's choirs and such is a token system. Each child has a ziplock bag on a wall/board with his name on it, and they get a token for doing good things. Sitting quietly during a story would earn them a token. Following instructions, speaking only after raising a hand, etc. At the end of the week, each child can spend his tokens at my "store"(a la Chuck E. Cheese). I use a similar system with my high school kids, but its not tokens.