If you are looking for a quicker and less expensive fix considering using draft busters slip underneath your doors to prevent drafts from flowing in and out. You can also caulk around your windows to help reduce the amount of hot and cold air moving in and out of your house.
People really don't realize how much of a difference this makes, I moved from a house with bad windows to a house with new windows, and not only did my electricity bill not go up even though I added 500 square feet, but I am able to better regulate the heat in my house. In my old house, my air conditioner worked overtime and sometimes could not keep up with the demands, in the new house we sometimes have to adjust the AC because it is too effective.
Put a Stake in Energy Vampires
Replace Your Lightbulbs
Low Flow Toilets
Fill a 20-ounce bottle (or two) with something heavy enough to weigh it down in the tank. Place the bottles in the tank upright so they don't roll around. The bottles displace the water and the tank does not fill as high which saves water.
Replace Light Switches with Motion Sensors
Did I miss a fix it and forget it project that could save me some money? Let me know in the comments.