The Head. There are only 2 types of heads a cock possess. The small head which carries a pea-comb and the large headed straight comb cock. Most cockers and breeders prefer small heads for aesthetic purposes. It's up to you to choose according to your preference.
The Eyes. Any color of the eyes will do as long as it's clear, alert and bright, well-proportioned, and well-focused. Most cockers and breeders prefer red eyes since it connotes American blood in them.
The Beak. Big thick beaks show that the cock can execute firm billholds, long thin beaks are signs of speed and agility, and hooked beaks are good for billholding too. Whatever the type of beak you prefer, it should close and set well, and the upper and lower beaks should fit in tightly.
The Face. The skin on the face of the cock should have a smooth red face. Rough faced cocks are either old and/or bred haphazardly.
The Neck. The neck should be well-proportioned with the body. Feathers around the neck must be full, shiny and smooth.
The Shoulders. Should be broad, muscular, and a bit wider in relation to the back and the rest of the body.