Classical period was marked by an increase focus on the real and more serious expressions. no more dopey smiles like archaic sculpture.
Early classical period work had more realistic bodies then archaic, but everything was still very ideal.
Both Early and late mainly kept very straight, series faces regardless of the situation the figure was in.
Late classical features elegant elongation of the human form, and the introduction of the female nude. The statues also became even more realistic in there figure.