Some research has indicated that homeopathic remedies were among the most effective treatments in the 1918 influenza outbreak.  Homeopathic remedies are easily obtainable at health food and some grocery stores, and worth looking into. Another thing that is extraordinarily effective is elderberry syrup, sold under a variety of labels.  It works by keeping the virus from being able to pierce cell walls, enter, and multiply.  Any simple thing you can do to boost immunity is helpful: Mushroom tinctures are excellent, drinking plenty of water and getting adequate rest are also important.  If you DO get the flu, of course get medical attention right away, and keep yourself hydrated.  Gatorade actually can work miracles in these situations.

Washing your hands and not touching your face are of PARAMOUNT importance in prevention.  A good discussion of handwashing, which I found informative, can be found here, at Simmons Naturals Soaps.  The products here are wonderful and can make keeping your hands clean a real joy.  Hand sanitizers are popular now as well.  I myself prefer a sanitizer made from essential oils.  I think they work better and don't have the potential to, in the end, actually lower your resistance to bacteria and viruses from overuse.  It is really important to make sure your hands are cleaned, somehow, after every transaction in the outside world:  The ATM, the grocery store, the Post Office, wherever you may be.  By not touching your face, or chewing your pen, you are keeping the bugs away from your eyes and mucus membranes, AKA The Entrance Point.

An additional, if subtle, precaution is to avoid being overtaken by fear of flu.  The body's defenses weaken when we are afraid, and invasion is more likely to be successful.   Remembering that these viruses and bacteria and microbes are around us, on us. all the time can help restore some mental breathing space.   The more pressured you feel about things, the more worried you are about stockpiling things "just in case", the more stress, in short: The lower your resistance.   Keep your balance, keep your hands clean, and you're way ahead in the game.  

Diffusing essential oils in the air at home is also a superior way to maintain adequate immune defenses.  The oils clean the air and also work on the mucus membranes, and the blood, to disinfect and protect.  Thyme oil is especially good in this regard, and can be mixed with other oils to increase its effectiveness and aromatic qualities.

I have many recipes for these kinds of remedies if you are interested.  Just email me with your questions!