Turn on the forehand and leg yield can be used to teach the horse that the rider's leg can mean something other than, "Go forward." The horse must understand this concept in these very basic movements before you will find much success with any of the more complicated lateral movements.
Allow with the reins when approaching a drop into water. Holding too much in the last strides can cause the horse to not use his body fully over the fence into the water - which can cause a stumble or fall on landing in the water.
From Facebook fan Gabby Ballin: "Some rides are going to be perfect. Some rides are going to have you wondering why you don't quit riding. When that happens, take a deep breath and go back to something you know you and your horse can do easily."
"If a horse won't stretch at the beginning of session, work on a contact sooner then stretch when he is ready." ~ Carl Hester
Too much inside rein is a common cause of horses missing their lead changes behind.