Today's helpful hint couldn't be easier:
If it's yellow, let it mellow.
If it's brown, flush it down.
Another solution is to fill a couple of 20 oz. plastic bottles with water and sink them into your tank. The bottle takes up area that would normally be refilled with water meaning that less water is used each time you flush.
Or do both and be a real hero!
For more information on conserving water go here.