Don't cut switchbacks, take shortcuts or make new trails. Know which users can use the trail, then be courteous and friendly to all. Avoid wet or muddy trails. Save them for future trips when they are dry. Keep your party small, preferably less than five.
Litter spoils trails and their surroundings.
Don't drop it, and pick up after others if possible. Never leave fishing gear and litter along water-ways. It can kill wildlife. Remove obstacles from trails for others when possible. Avoid disturbing wildlife, especially in winter and in calving areas.