1. Practicing Good Hygiene
The principal means for transferring a virus is through contact with an infected person. As such, it is important to wash hands frequently and to cover the mouth and nose when sneezing, using a tissue or handkerchief to cover your nose and mouth.
2. Staying Healthy
A healthy lifestyle helps your immune system to be in its best possible shape, giving you the best chance of being able to fight off the onset of a cold or flu. You will stay healthy by : Eating healthily, Exercise regularly, Reduce your stress levels, Keep well hydrated, Avoid smoking, Get vaccinated, Stay warm and Get your probiotics.
3. Taking Vitamins
Consider supplements if you believe in their utility. Take Vitamin C. Whether in the form of a tablet, drink, or fruit, vitamin C might help you prevent the common cold. Try some Zinc. Zinc helps the development of white blood cells which ensures that your immune system is functioning properly. Learn about Selenium. Selenium is a nutrient which plays an important role in the immune system. Prevent sickness with elderberry. A relative of blueberry, elderberry has been found to have powerful anti-viral properties. Add more garlic to your diet. Garlic has powerful anti-viral, antibiotic and anti-fungal properties and boosts the immune system in general. Boost your immune system with some echinacea. Try Quercetin. This has not only been found to have extremely high antioxidant characteristics, but it has also been found to have immune boosting capabilities, particularly when under stress, and especially when taken with vitamin C. Give Andrographis a try. Use more Coconut oil. Consider Goldenseal. Try some licorice. Drink black tea.
Source: http://www.wikihow.com/Prevent-a-Cold-or-the-Flu