Here are a few quick links to do some quick reading/learning:
Yorkshire Terrier Club of America (Awards) - About Size
Yorkshire Terrier Club of America (Awards) - A Responsible Breeder
Yorkshire Terrier Club of America (Awards) - About Color
Yorkshire Terrier Club of America Official Breed Standard - the Standard
Nows start reading some great books about breeding and yorkies - here are the first to start with.
The Complete Yorkshire Terrier by Gordon and Bennett
How to Raise Your Own Show Dog by Ann Seranne (She is Mayfair Yorkies and great information on genetics)
P.S. Hope you have a lot of extra money! This is expensive to do right.