It is common in my classroom on the left hand side of the white board to see a list of descriptors that outline the behavior that I would like to see in the class. I always explain to the class at the start of the year that this is a description of a good lesson for me. Please see the example below.
I make a strong reference to these statements a lot during the lesson, when the students are entering the class I am usually standing at the front pointing to the first descriptor. Secondly instead of asking for silence, I point to the next descriptor and the class usually react by quietening down. As I quiz the class I will point to the third descriptor if they begin to shout out and so on.
Over time the class get to understand the descriptors well and gradually begin to cooperate with me much more. The great thing about the descriptors is that I merely have to point to them rather than shout out. As I get to know my classes more I usually make a point of saying that these five descriptors are 'our goal' for each lesson - 'lets all work together to achieve them.' This works well as over time the class begin to nudge each other into following the descriptors.