Here are a few ideas:
Shut off or unplug anything that draws electricity that isn't necessary. (Toaster, Coffee Maker, Computer, extra T.Vs, Radios, etc)
Walk or bike to your destination.
Rethink your cleaning routine - What chemicals can be replaced?
Doing laundry? Hang a load or two out to dry (either on an outside clothesline, or on one of those collapsible laundry umbrellas)
Buy (or make!) some inexpensive cloth napkins to use in place of paper.
Visit your local farmers market and support environmentally-friendly farmers.
Pick up trash in your local park.
Start (or improve upon) recycling.Brainstorm - what else can you think of?
Let me know some other ideas - put them in the comment section.