You can also adjust the float height of your toilet float to a level just above where you toilet will completely flush. It's not going to save a ton of water, but it will save some and it's free.
I agree with the watering the lawn thing. If you are going to water the lawn, use water from a rain barrel. That's what I use on my feeble garaden. I also use the same rain water when I wash the car. A little dust/pollen/rain spots don't warrant a wash. Wait until it's good and nasty. You'll also appreciate the wash more that way. If you keep a clean car, you wife will never notice when you do wash it.
