The decade starts with dresses gathered slightly below the waist, almost hitting the hips on the second half; it only starts being accentuated again at the very end of the decade in the transition to the 30s.
Dresses start out loose and long, almost reaching women’s ankles as it was usual, with time, it becomes more fitted and they get shorter and shorter, and for the first time in decades, women were showing their legs. It is still important to notice, that unlike modern media presents it, no dress would be going over the lower edge of the kneecap, specially in day wear. Even in evening wear, the dresses would not go over the knees, the exception being performers. Another exception, of course, were young girls and teenagers, that could wear skirts above the knees, following Victorian tradition.
Another really big difference was the hair, a really characteristic trait of the twenty’s fashion. Due to WWI, many women left house duties and began working at factories and fields; and they could not afford to spend much effort in their hair. That’s when the bob came in; Hollywood stars and regular women alike cut their hair short, in a manner it was practical to care and style, discarting the Victorian belief that hair was a girl’s crowning glory.