Orange juice is actually not a good choice. Yes, vitamin C boosts the immune system, but sugar suppresses it. Unfortunately most people reach straight for the orange juice when they are sick in an attempt to get more vitamin C into their system. Although they are adding vitamin C to their system they are also adding sugar which slows down the body response. If you must have juice, although herbal teas and broths would be better, it is best to dilute the fruit juice so that you are taking less sugar. Even eating fruits is not necessarily recommended as the fruit sugars will still work to suppress your immune system.
Taking vitamin C tablets could prove beneficial in lessening the duration of a cold. According to the Linus Pauling Institute at Oregan State University, "The preventive use of vitamin C supplementation reduced the duration of colds by about 8% in adults and 14% in children."
Other food sources of vitamin C (not in order of nutrient) include brussel sprouts, broccoli, kale, sweet potatoes, tomatoes, bell peppers, swiss chard, collard greens, spinach, winter squash and green peas. There are others but these tend to be the highest.