There are many ways in which your house can become a power and energy leech but with a few simple changes you can save on bills and cut down on your footprint. these are just a few tips that I have run across and most are common knowledge but i feel it is necessary to state them here because i didn't some of these. plus this is my first ever Instructable so be nice. i am entering it in the Earthjustice United States of Efficiency Contest so please vote.
Step 1: lights
as everyone knows CFLs or compact fluorescent bulbs are the best way to take a chunk out of a few bills at once but there are a a few ways to make those bright beauties work better for you.
1. a CFL on there own reduce electricity use by around 75 percent depending on the bulb itself but the effectiveness of the bulb is cut by about 25 percent by being on dimmer switches and tend to burn out a lot faster than normal bulbs.
(edit: as valhallas_end said it is not a good idea at all to put CFLs on a dimmer only bad things happen like burning the bulb out or hitting the breaker.)
2. similar to dimmer switches, electronic timers tend to cut the life of the bulb as well.
3. for those lights you use the most often or you want to leave on for long periods of time LED light bulbs are a great alternative to the normal incandescent and the even the CFLs. plus LED bulbs last a lot longer than normal light bulbs.
4. in the theme of not leaving lights on motion sensor lights are the best, they turn on only when you pass and turn off seconds after you have left, little to no energy wasted.