Recycle your used motor oil and anti-freeze.
Take it to your local gas station or auto parts store. Don’t use draining receptacles with "absorbants" like sawdust or cat litter. Clean up spilled anti-freeze and don’t leave it sitting around open. It smells and tastes sweet to dogs and other animals and is highly toxic if swallowed. Call 1-800-RECYCLE for more information about recycling. And buy re-refined motor oil for your car.
... more information about recycling your motor oil

Fix oil leaks.
Check for oil leaks regularly and fix them promptly. Use ground cloths or drip pans under your car when you work on your engine. Clean up spills immediately.

Take care with paint, cleaners, and other chemicals.
Household cleaners, paints, thinners, and other household chemicals can harm streams when they are washed into storm drains and then into streams. Don't wash brushes or painting equipment in the street or driveway. Dispose of paint, rinse water, and soapy water responsibly.
... more information about planning your painting projects carefully
... more information about safer cleaners

Sweep your walks and driveway.
Don’t use water for these cleaning chores. Rainstorms and garden hoses just wash the litter and dirt into the gutter and then into our streams.

Tune your car regularly.
Tuneups and anti-pollution devices not only help keep the air clean, they reduce the fallout from your exhaust that is picked up by runoff on streets and parking lots.

Keep suds out of the storm drains.
Use low phosphate soaps or cleaning/waxing compounds when you wash your car. Wash your car on the lawn (not the street) to take advantage of natural filtering. Or take your car to a commercial carwash, where washwater is treated or recycled.