Don’t use settings meant for stores or sports bars
When you first switch your TV on, choose the home mode rather than the retail mode. Then use your remote control to select standard, movie, or cinema mode rather than dynamic, sports, or vivid mode. In our testing, these two simple changes can often cut power consumption by 20 to 50%!

Calibrate the brightness and color
Have your television professionally calibrated or use a test disc to calibrate it yourself. This step can help ensure your television looks best in a fairly dark room, saving energy and helping to replicate the experience of going to the movie theater.  For more information, see http://www.tomsguide.com/us/hdtv-calibration-isf,review-1190.html or  http://www.avclubhouse.com/2009/09/03/thx-study-shows-tv-calibration-saves-energy-by-50/.

Turn the lights down low
Turn down the lights in your TV room. By minimizing the amount of light that lands on the TV itself or the wall behind it, you will not only save lighting energy, but also help ensure that your TV looks good at a lower brightness setting of its own.

If your set has automatic brightness control, use it
Automatic brightness recognizes the room light and adjusts accordingly to ensure your TV is never consuming more power than needed.

Make sure it’s off when it’s off
Plug your TV and other audio/video components into a smart plug strip. This will help ensure that once you turn the main device off, most of the other devices will turn off automatically as well.  For more information, see http://www.efficientproducts.org/product.php?productID=24.

Unplug the unused
Recycle or at least unplug old televisions that you rarely use. Older models can use significant amounts of standby power, so it makes no sense to leave them plugged in if they will only be used sporadically.