A Wait stick. My students get very anxious and jump up and try to run up to the line even before i have called them. So to help reduce the pushing and shoving and the "I was sitting" being yelled out here is a wait stick. I used a large paint stick and attached velcro to it and then added the students pictures.
When introducing it I show the students that this is the wait picture and that when I come to them and show them their picture they may line up. Once I show them their picture I take it off and move on to the next child.
The students can see whose turn is going to be next and when their turn will be. It is also is great because the special helper (this changes daily for me) can always be first. If a child is not sitting nicely or jumping I show them their picture and remind them that if they do not want to be moved to the end that they need to wait and usually they start sitting nicely and quietly.
This year I have started using it consistently and it really has seemed to help!