We recommend you use cold water. You won't have to pay to heat the water, and your clothes will be just as clean.
Use the smallest load size you can for the amount of clothes you're washing.
Use the automatic functions on your dryer, instead of timed drying. The moisture sensor knows when your clothes are dry and will cut off before the timed cycle will.
Keep an eye on your lint trap and be sure to clean it out.
Be sure to check the vent trap on the side of your home as well. Keeping it clean can reduce your drying time.