First, it's great that you recognize that how you ride off road has consequences. Bravo. Having a conscience like this is the first step in riding responsibly. And, you're obviously far-sighted enough to realize how important responsible trail use is in cyclists gaining and keeping trail access.
The secret to trail preservation is practicing what's known as soft cycling. This is as much a mindset as a riding technique. It's being considerate of the trail and other users. It's constantly monitoring how you're riding. It's being in tune with your surroundings. If you can learn to ride like this, you'll minimize the effect your rides have on the trails -- and hikers and equestrians. Here are some rules followed by soft cyclists:
For more trail tips and information visit IMBA.