I highly recommend looking up the class schedules for both AMHA and AMHR (if you are looking at breed showing) and find a show close to you to attend. There really is a lot more to showing than just halter.
I teach my halter horses to whoa and set their back feet and then I shift their weight in their shoulders to get them to place the front feet and once again tell them to whoa. Then you have to find a way to keep their attention on you to keep ears up and get them to bring their neck to you. Keep in mind not to overstretch the neck. It should arch nicely, not come straight out at you. I am by no means a trainer so dont have any neat little tricks, I do something different with every horse it seems!
Then there is hunter and jumper! Both you need to start with ground poles and low jumps and gradually build up from there. Jumper for A is simply jumping the highest sets of clean rounds, in R it is fastest clean rounds. Hunter in both A and R is on consistency, well polished appearance, and clean jumping, if you take the course at a walk, you must stay at the walk, if you want to lope it, take the whole thing loping, I personally prefer trotting through it. The horse should stay centered over the jump and have nice form. Hunter braiding of the mane and tail is permitted. Show in a western type or nice nylon halter, not an arabian style halter.
Liberty is one of my personal favorites, great way for my horses and I to unwind and have fun at a show. You pick music that fits your horses movement, you must release and NOT touch your horse when you release and then you have to catch at the end of the time before the catch time runs out. Based on choice of music, use of arena, use of different gaits, and ease of catching. Can have a helper but only the exhibitor may touch the horse.
Driving is also a ton of fun, there are Pleasure, Country Pleasure, Western, and Roadster. You can look up the different divisions in the rulebooks for descriptions.
Versatility is a great class of Halter, Hunter, and Driving that is great for the all around horses.
Obstacle in hand is just as it implies, lots of obstacles in a pattern, sidepassing, groundtie (sometimes with feed nearby), bridges, groundpoles, pivoting, and other things may be found in this class. There is also driving obstacle with some pretty intense patterns that I have seen!
Showmanship is based on the handler and grooming. Proper fit of the halter, clean grooming, clean clothing, neat overall appearance, and a smooth performance of the pattern, pivot, and 'quarters' are what the judging is based on.
If I missed anything hopefully someone else will mention it.
Keep in mind practice makes perfect and you will learn something new every time you go to a show!
