Make a slide show about your life and your family and friends back home. You can also show some pics of things from your home country (making maple syrup / barbequing kangaroos / whatever). This is a great way to start making a personal connection. Also learn the difference between there and their. They're smart enough to pick up on mistakes like that, even if they don't know how to ask permission to go to the toilet in English.
And does anyone have any recommendations on how to play off of classroom dynamics and how that works at the high school level?