Ms. Moore,
For your procedures, such as entering the classroom, sitting on the rug, cleaning up, etc., practice the wrong way, and then the right way. Use a timer when pracicing the correct way, and have the students try to beat their time. For example, "It took us 57 seconds to enter the classroom corectly and sit on the rug. Let's see if we can beat that record." Kids love to set and beat records. When doing demos, try to continually engage the students by having them turn to their partner and tell the steps, describe the process, etc. They can gesture while you are doing the demo, that way their squirming is put into learning!
For the third grade class that is so mean to each other, have you tried working on a class quilt of some sort, where each individual piece would come together to be valuable in the whole piece? I would play calm music during class, and take the opportunity to use art to talk about beauty and value, and then encourage the students with kind words. Since you are their consistent teacher, engage them in positive learning, fun, kindness, and smart choices. Let them know that you believe in them!
Deb Weigel