Avoid eroded paths as much as possible, particularly during or after wet weather. You will do less damage going uphill, rather than downhill, on an eroded track. On zig-zags paths it is even more important to keep to the path. Cutting corners will create new channels for water to follow, thereby increasing the erosion. If there are specially constructed paths on or near your route use them rather than the ground to the side.
Litter is unsightly and can be dangerous to animals.
Even bio-degradable items like orange peels and banana skins take years to disappear. Take all your litter and try to bring back at least one extra item from each day out. Do not bury litter - animals will dig it up. Bury or cover your own body waste. Always bring home used sanitary protection and toilet paper.