After the "tomboy" look of the 1920s, there was a return to a more grown-up and sexier look that will characterize not only the 30s but also the 40s and 50s.In the 30s clothes were still simple but feminine and became even more sophisticated and glamorous at night.
Feminine curves were highlighted through the use of the bias-cut in dresses (this technique allowed the fabric to drape better and therefore the garment would fit like a glove, similar to the effect that jersey/stretch fabric offers).
Through the mid-1930s, the natural waistline was often accompanied by emphasis on an empire line. Short bolero jackets, capelets, and dresses cut with fitted midriffs or seams below the bust increased the focus on breadth at the shoulder. By the late '30s, emphasis was moving to the back, with halter necklines and high-necked but backless evening gowns with sleeves. Evening dresses with matching jackets were worn to the theatre, nighclubs, and elegant restaurants.
Skirts remained at mid-calf length for day, but the end of the 1930s Paris designers were showing fuller skirts reaching just below the knee; this practical length (without the wasteful fullness) would remain in style for day dresses through the war years. 
ACCESSORIES
Gloves were "enormously important" in this period. Evening gowns were accompanied by elbow length gloves, and day costumes were worn with short or opera-length gloves of fabric or leather.
Another key piece in the 30s was fur: extravagants pieces of fur decorating the garments or worn as wraps or coats were the final touch to finish that sophisticated look.
HAIR
Short hair remained fashionable in the early 1930s, but gradually hair was worn longer in soft or hard curls.
Hats were worn for most occasions, almost always tipped to one side and decorated with bits of net veiling, feathers, ribbons, or brooches.
Info taken from this link: wikipedia
