I can carry 70 gal. of fresh water in my tanks. I get about 2 weeks out of 40-50 gals.
Some areas may have water avail. so I can top off the tanks when needed. I carry those 6 gal jugs from walmart to be able to cart water from hard to get at spigots or wells.
My black tank carries 50 gallons so I have enough room for about 3 weeks of use. I go easy on the water level used to flush.
Baby wipes are great if you boondocking in the woods. Swims in ponds are good too
Sort of like tent camping but with luxury.
If I am dry camping with others ( fairgrounds/shows etc..) I will use the shower every two to three days but there is usually water in that type of camping so it's not a problem.
Those new paper plates are great ( dixie ultra ) they microwave with water and don't get soggy. Doing dishes uses too much water. If I use a regular plate or cup I try to wipe it with paper towels first and a very light rinse and wipe. Everyone has their own cup/plate to take care of.
Everyone will get different results, I could conserve more but I usually don't do more than 3 weeks in the woods, and I have been doing it enough I can pretty much judge what to use as I go. I find the people I take with me use more than I do or they forget to really conserve. Leaving faucet dripping etc...
Shaving.. heat small amount of water in a sauce pan and dump in sink. Running the water from the hot water tank uses too much water.
Lots of little things depending on how crazy you want to get