Grocery shopping: take your old bags back to the store and have your items put in them again.

Getting around town: Ride your bike instead of driving the car whenever possible. You get a great cross training workout and save gas.
Another way to save gas is turning the engine off when you’re not moving, i.e. in a drive-through, waiting for people you’re picking up, or waiting for a train to pass. In a mall, don’t drive to every single store, but walk between them.

I’d like to add one more suggestion, and defend the maligned plastic bottle. The plastic bottle is a perfect example of Reduce, Reuse, and Recycle.

Reduce: A perfect use for plastic bottles is in mixing up just enough powdered energy drink for a single use. This is a HUGE environmental impact, as it takes orders of magnitude (factors of ten) less energy to ship powdered or concentrated drink mix than it does to ship hydrated stuff. Water is heavy stuff. And it’s a shame that we send it using fossil fuels, as the western public water supply is one of the finest public health successes in recorded history.

Reuse: Properly cleaned, plastic bottles will last nearly forever.

Recycle – Most bike bottles are recyclable with normal plastic. When it’s worn out, put it in the curbside pickup, and let it get remade.

A couple of other suggestions:
1. Run from home or the office – don’t get hung up on finding the “perfect” place to run.
2. Actually use those race shirts to run in.