
There is a large element of luck to it to the swans sometimes turn into geese and the ugly ducklings into swans. If the parents are to yoru liking then all one can do is make an educated guess. If it were simple then the breeder would make a champion of every dog they keep :D
There are probably more potential champions in pet homes than there are in the ring. Certainly it is not unusual for a dog from a well bred litter to come into showing as an adult in our breed and do well, and the same in many others.