You can help the environment by "going green" whenever you make environmentally friendly choices in your everyday life.
Examples:
Walking instead of driving
Combining errands into one trip instead of making multiple trips
Carpooling (less fuel/pollution)
Using Mass transportation (less fuel required per person)
Buying organically grown food (no poisons into the environment)
Buying food grown locally (requires less delivery fuel/pollution)
Buying items made from recycled materials
Recycling
Etc.
Basically it means to think about your everyday choices and how they impact the air, water, land, and the future. Then make choices that have the least negative impact or better yet choices that make a positive impact.
http://www.coopamerica.org/
http://www.thedailygreen.com/
