Leaving No Trace is a great way to think of your time out hiking. But is it enough? When there are hundreds or thousands of hikers who don't respect LNT hiking and camping values, I don't think it is.
So I like to practice leaving a negative trace, which basically means I try to help restore things back to what they might have looked like if disrespectful humans hadn't been there. Negative trace is about reversing any negative impacts that humans have caused in nature and can be as easy as bending over and picking up a stray trail bar wrapper.
Some cool examples from Backcountry Attitude:
Top: "These rock seats & fire ring were far off the beaten path and I was very surprised to find them. Needless to say they were spoiling the view.I think it only took 10 minutes to dismantle everything and naturalize the area. When the vegetation fills in you won't know a fire ring was here." Bottom: "This rock fire ring was far from the main trail and hadn't been used in years. A little effort can make a big difference. Took me only 5 minutes."