At first symptoms of sore throat, cough or sneezing/runny nose, take oscillococcinum (a homeopathic remedy). Repeat doses as directed. Six doses will deflect any typical winter illness if taken at first symptoms.
If you don't have any oscillococcinum at hand when symptoms appear, use Old Indian Wild Cherry Bark Syrup (a commercial preparation) and/or use aromatherapy.
For aromatherapy, I sprinkle oregano oil, eucalyptus oil, clove oil and lavender oil on a cotton cosmetic pad. This pad can be attached to a fan and the aroma will fill the room and kill all the fungus, bacteria & viruses in the room (including your nose and throat) as you sleep.
If you're on the go, you can take the pad with you in a plastic bag, sniffing it as often as possible. It'll clear your nose, soothe your throat and help kill off the viruses/bacteria in your nose and throat.