Can you think of advice that proved especially helpful to you? What was it, and why was it beneficial?

If I go back to the days of my student teaching semester, I did get some good advice from my supervisor when it came to students becoming unruly in teh classroom.  The one thing I remember is if things are starting to get out of hand, if they are away from their seats, tell them to go sit down in thier chairs and be quiet.  Make sure that every student is quiet and ready to participate again.  When they are, continue the activity as you have planned it to go.  This was beneficial to me because it helped me to have better classroom management.