Lay out rules early on in the year to establish your assertiveness. Prevent behavior problems by giving preschoolers limitations -- such as not allowing them to talk out of turn, fight or hit each other, or play with toys when they are scheduled to do something else. Intervene immediately by showing a student the right way to do something, if he does something not allowed. Encourage students firmly by showing them how to play gently and get along, and then providing positive reinforcement when they do.
Set cues for getting students' attention. For instance, teach them that if you flash the lights on and off, they must stop what they are doing and pay attention. Or establish a clapping system where if you clap three times, students must clap the rhythm back to you and pay attention. Also establish a cue for students to know when it's time to clean up and assemble in a circle.
Deal with behavioral problems quickly when they come up. Remove a student's privileges if he does not comply with the rules after you have asked him to. Give a students a time-out if they are fighting or not playing nicely. Establish other standard disciplinary procedures, and follow them quickly and consistently.