Slow down and use caution when approaching or overtaking other trail users. Before passing another trail user, be courteous and make your approach known well in advance. Bicyclists and skaters yield to walkers. Bicyclists yield to skaters. Downhill users yield to uphill users.
Faster users yield to slower users.
Never spook animals - this includes not only horses on the trail but livestock in adjacent fields as well as wildlife. Respect wildlife - you are a guest in their territory. Do not pick, dig, or damage plants. Be predictable - travel in a consistent and predictable manner. Always look behind before changing positions on the trail.