One of my water conservation programs consists of taking really short showers--wetting myself down, soaping up with my shower scrunchy (uses very little soap and absorbs no water), and then quickly rinsing off.  I wash my running shorts on the floor of the shower in my "rinse water" using the soap water from my body, then rinse in fresh water.  If I have several clothing items to wash, I wash these in the galley sink with salt water, and then rinse in fresh water.

When cooking, use the least amount of water needed.  Its amazing how little water it takes to boil pasta.  Using angel hair or other thin pasta not only saves propane (shorter cooking time) but also it requires less water to boil it.  Also, if you are making two items needing to be cooked with water, you can finish cooking one, and drain the boiling water from that item to cook the next item—hey its all going to the same place.

I also have a couple pump bottles of antibiotic hand cleaner around.  I keep one in the cockpit and one in the kitchen.  Instead of running a bunch of water to clean your hands or freshening, the antibacterial liquid is quick and easy to use and you don't need water.

I've heard of people who make a rain catcher out of their Bimini top.  This may be a good idea-- if it rains,  so relying on that method to obtain water is iffy, at least during the winter months.  You can also dam up your water tank input with a towel when it rains to catch the fresh rain water (after the deck has washed off of course).

Other than having a water maker (and make water like crazy when you find a clean or isolated anchorage), a salt water pump in the galley, water conservation program, and learning to cook with minimal water, plan to fill up every time you find some decent potable water, even if it just means topping off the tank.