I am a visual learner, so I tend to do things in my classroom geared toward that. I hang THISsign up on the board. I use a cute pointer magnet to let the students know where I want our class noise level to be at for that activity. I will give them reminders before we begin such as "Take a look at the level for the activity. I expect everyone to be working in the Yellow Zone." It works great. I love it especially during guided reading and center time. When the noise level starts to get too loud, all I need to say is "RED" and they quiet down again. Of coarse it takes a lot of training those first few weeks of school, but saves you the rest of the year.