Clearly define your expectations about the children's behavior. Many young children may not have experience in participating in group educational settings, so don't take for granted they already will understand how to behave. Remind children of the expectations on a regular basis with verbal coaching. Place signs around the room that use pictures to illustrate the rules, since most children in this age group can't read.
Limit activities, such as craft projects and worksheets, to short intervals. This will better accommodate children's shorter attention spans. Change activities every 20 to 30 minutes, but give kids a countdown a few minutes before each activity will end. According to the National Association of Child Care Resource and Referral Agencies, children in the preschool years often have difficulty with making transitions. You can avoid meltdowns by teaching children what to expect and when.
Follow a structured routine each day. Common preschool routines include a circle time when students gather for sharing, free choice, story time, arts and crafts, clean up and snack time. Routines help to prepare children for what to expect in their day and is good preparation for their future school years, which will follow a predictable schedule.