Better insulation, udated heating and air conditioning, umm... seal or replace windows and doors. Unplug unused appliances. Keep plants in the house, and use no ANTIBACTERIAL soap, as it is bad for the environment.
do you subscribe to the planet green network? it's available on cable and satellite... they have great tips. Also go to their website, I'm sure there is tons of information there.
a small thing you could do it make sure you turn out the lights you are not using.
Also unplug appliances you're not using such as the toaster or the microwave. even your cell phone charger and TV should be unplugged when you're not using it. They still use energy when they're not on.
you can wash your hands in cold water so you don't waste water waiting for it to heat up. It still kills the germs because you use soap.
I've been reading a book "green generation" and it has all sorts of tips. it's main focus is to think both Big and Small.
thinking small is recycling and turning off the lights in your own home. Thinking big means you take into consideration the impact you make on the world as a whole because of the decisions you make. for instance eating vegetables grown locally as opposed to getting vegetables that are grown out of state. if you buy locally you are not contributing to all the fuel being used to transport all those veggies from one state to another.
I recommend the book. I got it at the zoo, but I bet you can get it at a bookstore.
here's lots you can do - and there's also one website called Care2 (www.care2.com/ ) that has its own newsletter with new tips, as well as discussion groups. Do check it out!
A good start is to put in plenty of green plants, use soap and water (not synthetic detergents) to wash the house with - and open the windows as much as possible, for good air circulation.