You are being judged from the minute you enter the ring to the minute you exit, so give yourself every opportunity to succeed.
Plan your entrance
You are presenting yourself and your horse to the best of your ability, so plan your entrance accordingly. To start with, enter the ring and pick up the right diagonal and canter lead. You would be amazed at the amount of times I see this done incorrectly! Even in the hunter classes the correct diagonal is important, although not as much as in the equitation ring, where picking up the incorrect diagonal is certain death and puts you out of the ribbons immediately.
In the hunters, determine the best way to show your horse off, both entering and exiting. This depends on your horse: if it has a bad trot, walk in and pick up the canter to show off the better gait. If it has a good trot, show the trot before you pick up the canter.
Never forget the showmanship aspect of the horse show. It seems a minor thing, but you should have a nice expression on your face when you enter the ring. When someone walks in the ring looking like they are madder than heck, it doesn’t give the best first impression to the judge. It goes without saying that you should be neatly and cleanly attired and that your horse should be well presented.
If the first fence is coming towards the gate, avoid trotting to the far end of the ring and doing a circle. In my experience, judges also get really irritated when you trot into the ring, do a transition to the walk and take too many steps before you canter. There is also no need to walk to the far end of the ring. If you are trying to hide a bad trot, walk in, pick up the canter and go to the first jump. Go into the ring, be efficient, and get to work.
Leave a good impression
Once the course ends, get your lead change and make a nice transition to the horse’s best gait. If the course ends at the far end of the ring, a circle is not necessary, but if you finish by the gate, a closing circle allows you the chance to wrap up in an organized manner and leave a good impression.
In the equitation classes I always say never sit the trot on the way in or out of the ring (unless you are Anky!) I also personally dislike riders petting their horse on the way out of the ring. In the ring it’s showtime and I don’t think you need a flamboyant demonstration of emotion as you come out. And finally, I like to see riders maintaining contact until they are out of the ring. It is counter-productive in a hunter round when riders drop the reins on the closing circle. Keep it together and finish professionally.
If your horse has missed the change while you are on on closing circle, I believe the best course of action is to complete a downward transition without a fuss and cross your fingers that the judge wasn’t looking. If you start training in the ring you know you have no chance, but once in a blue moon the judge won’t be looking your way.