Using a low-flow showerhead (last post) can definitely conserve water and energy to heat the water.
Along those same lines, we also reduced the temperature on our water heater. The only noticable difference is that the hot water control is turned further to the left, thus mixing less cold water. If your water heater temperature is set above 115 degrees, you are probably heating water hotter than you need it and could save some money by turning it down. Many of the newer dishwashers and clotheswashers have with built-in water heaters, you might be heating the water twice.
Reducing energy costs will enable you to live a more sustainable lifestyle by reducing monthly bills.