The best way to learn how to boondock is to do it. Start with a night or two in a no-hook-up campground, where help and advice and probably a water faucet are available. Talk to other boondockers. Keep a log of what situations shortened your boondocking trips, such as running out of fresh water, gray water tank filling up. Then find ways to overcome them, i.e. carry extra jugs of fresh water, reduce your use of fresh water, etc.
The next step if finding boondocking campsites. Start with public lands administered by the BLM and National Forest Service, as well as Corps of Engineers, state fish and game refuges, state forests, etc.
For even more information, check out my ebooks: [I]Boondocking: Finding the Perfect Campsite on America's Public Lands
and 111 Ways to Get the Biggest Bang for Your RV Lifestyle Buck.
or go to my Healthy RV Lifestyle website
for more RVing info. Happy travels.