Hi, one day is enough for you to visit most of the highlights in Shanghai. I recommend the Shanghai Museum, Yuyuan Garden, Huangpu River cruise, Shanghai World Financial Center or Xintiandi to you. If you prefer to go shopping, then the Bund area and Nanjing Road are the good choice. Or you can spend one whole day to take a side trip near Shanghai, such as famous Water Town Zhouzhuang or Suzhou.