I'm becoming more and more insistent about turning off lights (CFL of course), turning things off at the mains and tracking down every last phone charger left plugged in.
One of the most powerful things I think you can do is ring up your energy supplier and ask for your yearly kWh usage for gas and electricity. Not only can you use the information to find a cheaper tariff, you can set yourself goals on how much energy you think you should be using.
What amazes me is the different amount of energy appliances use. My tumble drier costs a fortune compared to my projector. Evidentially I should be watching more movies and washing fewer clothes 🙂