various trail etiquette

Slow down when you pass instead of splashing muddy water on other riders as you pass them. 

Normally you would hold your hand up with the number of riders BEHIND you then the last rider would hold up a closed fist as the indicator to the end of the group..

Those who are going uphill should back down and let riders pass downhill.  It's not safe to back up uphill due to blind spot for others coming over the downhill.

Pull off to the side of the trail when you stop please.

Detailed Trail Etiquette

First guy in front of 20 riders (or any group longer than you can see) would hold up five fingers.  So anytime you see a rider hold up five fingers, it means five or more riders.  Sometimes riders get creative by flashing five fingers two times meaning ten riders, etc...

The 2nd to the last guy would hold up one finger last guy would then hold up a closed fist to show he is the end of the group.

When people come up behind you be considerate & let them by.  Just pull slightly to the right.  Some riders like to go fast & others just want to take their time.  Letting faster riders pass is polite & obviously good etiquette.