You can recycle motor oil at most filling stations or at a local recycling station. Use automatic carwashes that recycle their water. If you want to wash your own car, do it on the grass, where excess water can be absorbed by the ground. Try to use a phosphate-free soap or try pressure washing with water only. Keep your lawn vegetated.
Roots help hold soil and even absorb chemicals before they can wash into a storm drain or stream.
If you have a stream on your property, maintain a buffer of vegetation around it to protect it from runoff and to maintain the integrity of its banks. Consider an oyster shell or gravel driveway instead of pavement. Consider a wooden deck instead of a concrete patio. Use mulch to help prevent soil loss and runoff. Keep your grass between two and three inches tall.