Don't leave the refrigerator open!

One of the things I've been trying to teach my 3 year old daughter recently is not to leave the door to the refrigerator open too long. Of course, we're also trying to teach her to be more independent, so the two aren't exactly going hand in hand. Reminding her about conserving energy, though, has drawn my attention to ways that I can make our refrigerator more energy efficient. Here are some things I do:

• If I have something warm I need to put in the fridge (like leftovers or tea) I wait until it's cooled down to room temperature.
• If I'm going to use a frozen food in the near future, I let it defrost in the fridge. As the food defrosts, it's also cooling down my fridge!
• I've done the dollar bill test to make sure that the door is closing properly. If your refrigerator door can hold a dollar bill tightly when closed, then it is sealing properly
• I try to keep the freezer as full as possible and the fridge cleaned out. The freezer works more efficiently when full and the fridge works more efficiently when there is enough air for circulation around the food.
• Also, I haven't but I know I should be checking and cleaning the freezer coils.

Do you have any other tips?