I don't know if you live in a region where you need to consider heating your house. I live in Sweden, so making a home more energy efficient is almost always a matter of making heating as efficient as possible around here.
One way to do it is by investing in thermostats connected to your furnace, if you have one. In our case, we have a thermostat on the middle floor (away from any sunny windows, the kitchen or other heat sources) that tells the furnace the temperature of the room and the desired temperature of the room. When the temperature of the room drops below the desired level, the furnace starts. I think we got our thermostat for less than the equivalent of 50 dollars, but it was a long time ago.
We also have an accumulator tank, that helps the furnace work more efficiently in that it helps it heat the water in our radiator system/hot water more efficiently.
Each autumn, we go over all our windows. Checking for drafts and fixing them. Since drafts is lost energy.
Besides making sure your house is properly insulated, if living in a cold climate, you might want to look over all of your appliances ranging from that electric kettle to the back-up hard drive. Sometimes, it can be worth updating certain appliances before their time just because of the cost of running them. Don't forget all those lamps!
Toilets, taps and shower heads might also be a good idea to look over if you are looking at becoming more energy efficient. Especially if you are heating your own hot water.
Other than that...it goes without saying that you should of course try to avoid using electricity as much as possible. For instance, how often do you hoover? In my family, it's about once a month since we generally reach for the classical broom and dustpan for everyday surface cleaning. Do you turn the lights on in the bathroom, even if there's enough daylight to see by and you are not planning to do anything that really requires you to see properly? How about your computer, do you turn it off when you know you are going to be away from it, cooking dinner and tending to the household in large?
I firmly believe the biggest changes we can make to save money generally is changing our own habits.