Scroll all the way to middle of the page and it'll give examples of the "perfect" features of a Yorkshire Terrier. Unfortunately, there are no perfect specimens so you have to pick what'd you'd be okay breeding vs not breeding. Like for example my breeder's dogs had to have a good bite, nice earset, and level topline but she'd never breed a cottony coat unless all other physical attributes were astounding.
Yorkie, Yorkshire Terrier Photos