Some of these suggestions are common sense and we've all used them for years but others are specific to us RV'ers.
Position your RV to maximize day-lighting
Install window films to reflect sunlight and heat
Take shorter showers
Turn the water off completely after you take a shower
Routinely inspect your outside water connections for drips (please report leaks to staff).
When brushing teeth, shaving or washing hands, turn the water on only as needed
Rather than watching TV, go for a walk on the creek or go birding
Use less paper products: plates,cups, etc.
Use less laundry soap. Research proves the "recommended" amount is way more than needed. Try homemade laundry soap and fabric softener, it's better for the environment. Learn how here.
Replace your incandescent lights with compact fluorescents or LEDs
Set the temperature of your refrigerator between 36-39° F.