Follow the service schedules listed in your owner's manual. Replace filters and fluids as recommended. Check your tires for proper inflation. Underinflation wastes fuel your engine has to work harder to push the vehicle. Properly maintained tires will last longer, meaning fewer scrap tires have to be disposed.
Air conditioners contain CFCs-gases that have been implicated in the depletion of the ozone layer.
Many repair facilities accept these items. Or call your local municipal or county government for recycling sites. Never dump used oil or anti-freeze on the ground or in open streams. Observe speed limits. Mileage decreases sharply above 55 mph.