how can i prepare my toy yorkie for dog shows?

I have to concur with all of the answers. You start with your breeder. Hopefully you purchased from a show breeder. They can help you get started. You will need to attend a lot of handling classes for yourself as well as your dog. With a coated breed abviously coat care is of primary concern, and a Yorkie coat is especially time intensive. If your breeder doesn't live in your area there is probably an AKC all breed club and you could contact them regarding classes. As another person suggested go to the national club's web site, it can be a wealth of information.