At its most basic level, energy efficiency means turning stuff off, or turning stuff on less often.  The following list generally covers variations on that theme:

• Develop a routine for turning off unused devices.  Pick 2 or more convenient times of day, say before you go to work and before you go to bed, and perform a quick walk through of your home, looking for lights, fans, electronics, etc. that won't perform any useful service for the next several hours.  You'll be amazed by how much stuff you can turn off this way.  Use this walk through to check your thermostat too.
• Only run clothes washers and dishwashers when full.  Use cold water for washing clothes.
• Turn the temperature of your water heater down to 120 degrees.
• Try to keep your refrigerator and freezer relatively full(use water bottles if necessary), and vacuum the coils to help it run more efficiently.
• Unplug small kitchen appliances with clocks(Vampire Alert!) when not in use, e.g. coffeepot, toaster oven.
• Compost(or, less ideally, throw away) your food scraps rather than using the garbage disposal in your sink.  This saves water, too.
• Reduce to a minimum any outside lights you leave on all night.
• Experiment with air drying clothes to reduce electric dryer use.
• Take a hard look at small electric personal care devices and reassess whether they are really necessary - you may decide they are, which is fine.  Examples: electric shavers, hair dryers, curling irons, electric toothbrushes , clothes iron, humidifier, air cleaners/filters, etc.  House plants clean and humidify the air without power cords.  Many synthetic fabrics look and feel fine when air dried.
• Watch less TV.
• Turn the computer off unless you'll need it again in less than an hour or two.  Use the settings to have it automatically enter sleep or standby mode after 15 minutes.