Ride Better With One Rein Riding

the cue with the rein he must respond immediately. I am looking for three responses from the horse stop his feet bend his head towards me and relax. 
When the horse accomplishes all three and I release the rein pressure I rub him on the neck and just let him stand. This reward gives him a chance to calm down if he is nervous and really relax which reinforces to him that he did well.
Although its a rare occurrence a horse is capable of running away with his head turned sideways even with two reins and a bit. Practice the neutral lateral bend in small safe area to teach your horse that when you bend him he will automatically stop and relax. This way if you are ever in a real emergency you can go back to this foundation block that you have built and stop your horse. 
Next I progress to the open direct rein which simply means to use the rein as a direct signal to turn while I use my seat and leg to reinforce the cue. For example to turn right I put a feel on my right rein and press with my left leg and seat. 
The key with open direct rein is that it doesnt require any vertical flexion in the horse. At this stage I dont want to layer too many requests on the horse such as looking for lateral and vertical flexion at the same time. I want to isolate each maneuver as I teach it breaking everything down to make it as simple as possible for the horse.
FIGURE 2
The open direct rein connects the horse to my seat and leg aids which are stronger cues than my light guiding rein. For example in FIGURE 2 Im opening the door and giving him cues to move left with my rein and leg aid. At the same time Im shifting my weight onto my right foot to allow him to move his body to the left with greater ease. Leaning the other way would make it harder for him to move over because Id be standing in his way. Interestingly I have found motorbike riders have a harder time with this concept due to their having been taught to lean into a turn. 
One rein riding with a rope halter over obstacles lets you attempt the obstacles without accidentally interfering with the horses
mouth and gives your horse a reason to respond to your cues. 
For example if you jump a log there is no bit to bang his mouth if you accidentally balance on the reins during the jump. Or if there is a tree growing in the way your horse knows he cant go through it he is naturally ready to go left or right to get around the tree so when you ask for this it automatically has more purpose than if you cued for a sideways step in an empty arena.
As you gain more confidence in your horse get creative and have fun finding new obstacles to tackle.