This is my method I use for many grade levels including middle school students. It has worked many times for me. It usually leaves the student scratching their head and not knowing what to do next. Scenario: Student refuses to move seat when asked to, due to his constant talking with others around him. Solution, move the other students around him or her. I have moved whole group tables and left the defiant one sitting there all by him or her self. It gives a smile every time when he or she can't figure out what happened. With younger children that I have some control over discipline ie; sit out recess, I simply tell them if they talk to the student in question they will be in trouble, this to seems to work for me.