Proper preparation is essential in maintaining a structured class. Being prepared gives you extra time that would otherwise have been wasted towards looking for the supplies.
Always have red pen and #2 pencil(s): These are essential items. The #2 pencil for role call and the red pen used for grading, marking and important notes. Don't assume these items will be available as the teacher may have taken them home, or hidden them from others to get.
Have a Whistle (Optional): This is to be used if you are subbing for a Physical Education (P. E.) class. It is common that you will be teaching more than one class so always be prepared.
Active Early: Come at least 1/2 hour before class starts. Usually many duties are involved before class starts. Including: finding the school, finding the parking lot, finding a parking space, fill role of hall monitor (if assigned), finding classroom, finding roll sheets, find lesson plans, review materials for day, learn school procedures, and plan your own strategy of teaching plan for the day.