The first hiking etiquette thing that you need to know is that there is a hierarchy on the trail. Horses have priority, followed by hikers, and then bikers. It’s pretty simple to remember and makes encounters much more pleasant when everyone knows who gets to go first. Always check to see what other kinds of travellers will be sharing the trail with you before you start. If horses or bikes are allowed, then be mentally prepared to encounter them.
See 6 Reminders on Hiking Etiquette at http://www.artofmanliness.com/2013/10/18/6-reminders-on-hiking-etiquette/