A sweater, especially in a flattering color with a great neckline can really showcase the beauty of your upper body. Some men go as far as to say that beautiful girls wearing tight sweaters is what makes winters bearable for them. I am sure as people read this statement there will be many a nod of agreement.
How a beautiful girl pulls of wearing a sweater to look better, is of course totally dependent on her. If she is petite, then a sweater with big print on it in a really bright color with a high or polo neck will really make her stand out. If she is more on the well endowed side, than a dark sweater, preferably plain or with self design on it with a wide or deep neckline will add to her beauty and grace.
The thing about a beautiful girl wearing a sweater is totally about how she makes it work. And you thought sweaters were just winter wear to keep you warm!