Instead of stating that it's time to end one activity and begin another, use music as a means of calmly transitioning your students from one task to another. Play a CD of soft music, perhaps classical music or children's tunes, when you want your students to complete the activity they are currently working on. Help children learn that, upon hearing the music, they should clean up what they are doing and assemble in the common meeting area to learn what they will be doing next.
Use a jar and beads as an incentive for smooth transitions in your kindergarten class. Once your students are lined up, carry a clear jar with you as you walk from one area of your school to another. If your children remain in a straight line, keep their hands and feet to themselves and walk quietly to and from the location, place a bead in the jar; if smooth transition does not occur, remove a bead from the jar. Once the jar is full, award your students with a simple prize: perhaps five or 10 extra minutes of recess, a small party, stickers or anything that is appealing to them.
Simply lining up to move from your classroom to another area in the school can often prove to be a chaotic activity for kindergarteners. In order to avoid that chaos, have your students line up based on attributes. For example, you may say "children who are wearing blue may line up," or "children who have a birthday in the month of July may line up." Upon hearing the attribute you describe, children with the stated feature line up.
Oftentimes, children can become impatient and rowdy when they are waiting for a prolonged period of time. When your students are standing in line waiting for their turn to use the restroom or waiting for their buses, discourage bedlam by engaging them in finger plays. Lead them in reciting the finger play "Where Is Thumbkin" or "Five Little Monkey's." In addition to keeping order, you're also helping children develop their vocabulary and learn how to expand their patience.