Run Full Loads
It sounds obvious, but if you only run your washing machine and clothes dryer when they are full, you'll save in the long run. (Same goes for your dishwasher, incidentally.) Also check your clothes washer settings; try quick cycles to reduce wash times and high-spin modes to reduce the need for drying. On your clothes dryer, use moisture sensors if available and don't forget to remove lint from the filter in between every load to keep your machine running efficiently.