One of the biggest factors of your utility bills is your heating, cooling, and lighting. Surprisingly however, many people don't use what mother nature already gave us - the sun and wind. I notice that whenever I am at someone else's home, they more often than not have the blinds shut tight and all the lights on in the house, in the middle of the day.
At our house we have a pretty good system of heating, lighting, and cooling. During the summer months we adjust our blinds and open windows to keep the heat out, let the breeze come through, and light up the house. During the day we rarely have a light bulb on because all our blinds are open.
To keep the heat out, we shut all the blinds during the day when we are not home to create a dark, cool house. When we get home we fully open all the blinds on the side of the house that the sun is not striking. On the sunny side, we crack them upwards so that light gets in but does not shine on any walls, furniture, or floor (if anything it shines on the ceiling, which of course also helps lighten the room.
We also select windows to open based on the direction of the wind to maximize the breeze coming through the house. If it's cool enough outside, we just open all of them.
The savings on your electric bills are substantial, and as a bonus you get to sit down to breakfast and say things like, "the angle of the sun sure is giving us lots of light this morning."