Answer:
It depends on what type of show. Breed shows have their own rules and guidelines. Quarter Horses, Paints, and Appaloosas are very similar. These breeds will provide you with the rule book but there could be a small fee. You may also have to have a registered horse to show in breed shows. Arabians have full and half Arab classes but you must have your horse registered to this breed also. For non registered horses open shows provide the same fun for all breeds. The organization running the open show will have their own rules or may go by state rules. Either way plan ahead and get a rule book.
Halter can be a fun class if you know the ropes. Grooming and presentation of the horse and handler will make or break the class. You and your horse must be turned out perfectly. You need to know where to stand and move out of the judge's way as he inspects your horse. He may ask you to trot, pivot and back your horse and it must look smooth and flawless. If you have a friend or know somebody that can help you and give a little coaching it would be wonderful. At some tack shops and western stores they sell or rent instruction videos that may be a good investment. These videos are usually made by professional trainers and judges and are a good sourse of information.