Image via Wikipedia1. Drink less water.
2. Use the "water closet" sparingly. Because you are already filling up your glass less, you'll be urinating fewer times as well, which will save crap loads of money from being flushed.
3. Shower less. At first this one might cause some problems at work or with a partner, but explain that you care deeply for the environment and you are just doing your part in trying to save water. They will quickly apologize and thank you for your efforts to go green.
4. Wash hands with less water. It has been said that you should wash your hands for as long as you can sing the entire "happy birthday" song. In this case, simply cut it down to quick "happy birthday" statement instead.
5. Collect water from your roof for emergencies. It's tough to not use water, so grab some from that holding spot so you have some available, just in case you need some.
Obviously these suggestions are not for the novice thrifter. It takes dedication to save water...but I know what you're thinking: it's worth it.