The main benefit you personally will gain from an ENERGY STAR is the money saved from its usage. The secondary but as rewarding benefit is that you will be helping to keep the planet green. Here are a few guidelines:
Each set temperatures constant for at least 8 hours at a time.
Don't adapt the settings by overriding them regularly. You will save the most money by adhering to the settings.
If you must override, use the temporary button instead of the permanent/ vacation button. Using the permanent hold will not be as efficient and you may forget to unlock it whereas the temporary only holds the new setting until the next cycle.
If your unit has batteries, remember to change them regularly
Use more than one programmed set back if your home has more than one temperature zone.