Consolidate or eliminate old high energy consuming refrigerators. Use the energy saving capabilities on all classroom computers, and turn computers off when they're not in use by students. Local utilities often have grants or low-cost programs to help in such energy measures. Choose an energy monitor for your classroom every week who will make sure energy is being used properly. The monitor will turn off lights during recess and after class.
Recycling also saves energy.
At home, hold a ribbon up to the edges of windows and doors. If it blows, you've found a leak. Tell your parents. When you leave the room, turn off the light. Turn thermostats down to 68 degrees or below.