Mailing letters and packages have a large carbon impact, so if you must mail something, follow the lead of many eco-friendly companies by re-using packing peanuts, newspaper, air bubbles, and other packaging materials. In addition, don't immediately recycle cardboard containers (like cereal boxes, or any other items you buy), re-use them as shipping containers. You can simply remove the labels, and place new ones overtop.
This is a great idea and can really bring out your "creativity". My favorite is using pages out of a magazine to make envelopes. I've also used old posters and calenders to wrap presents.
If you use Ebay, this is an easy cost saver.
"If you don't like this option, take a look at the option, for reusing the water from the sink, and using it in the toilet. AQUS Water Reuse System"
hbomb7 on 9/2/2011 about the action Selective Flushing - you don't have to flush every time!