Double up on mulitvitamins, get some echinacea down you all washed down with whisky and you'll be fine. I hear Sainsburgers have pharmacy stuff reduced to 50p and Tesco has Gentleman jack at £15
If you catch it early enough first defence nasal spray really really does work - problem is you need to catch it at exactly the right point.
Other than that I stir some honey into hot lemon/orange cordial and/or drink plenty of whiskey but that just helps to offset the symptoms a bit.