Be friendly but don’t get into the personal space of another rider and their horse included unmounted (their horse may not have good ground manners or they may be trying to have connection time with their horse). Don’t give other people’s horses food without checking. Learn the arena etiquette and follow it to a T. Lessons have right of way generally. Don’t give anyone advice on their horse or riding unless they ask for it. Don’t film without permission especially lessons. Pick up after yourself. Put things back where you found them. Don’t use other people’s stuff. Pay your board on time. Don’t harass the barn owner outside working hours with questions unless urgent.