What can I do to help the environment?

I have been reading and watching a lot about the environment lately.It looks like our activities is increasingly putting a heavy burden on the environment and if nothing is done quickly we all may have to suffer greatly. I have started doing little things around the house to help improve the environment. One of the first things I did is to replace all my light bulbs to energy saving ones. I have also started to reduce my heating to 20 degrees instead of 25 or 30 degrees. I think more can be done by ordinary people in their day to day living. If you have any other ideas to help save the environment please leave it.