Keep a tape player and several different jazzy or upbeat cassettes in your class in a place that is easy for you to get to quickly. When it is clean-up time, line-up time, lunch time, recess, time to switch centers, etc., play the music so students know that it is a transition period. You might even want to use the music as a timer for certain transitions when students are first learning the daily class schedule. You can also give them a certain amount of time to clean up, lin up, etcetera, by playing the music.