Eat raw garlic, which has antibacterial and antiviral properties. Crush a clove or two and add to foods like soups and grains just before serving.A warm, humid environment created by a humidifier may provide some comfort.
The key thing to remember is that the annoying symptoms of a cold are part of the natural healing process - evidence that the immune system is battling illness. For example, a fever is the body's way of trying to kill viruses in a hotter-than-normal environment. Also, the heat from the fever makes germ-killing proteins in the blood circulate more quickly and effectively. So a moderate fever for a day or two will actually speed up the recovery process.
Coughing is another productive symptom as it prevents infected mucous from reaching the base of the lungs and creating secondary infections.
Decongestants are generally not a good idea as they work by restricting the flow to the blood vessels in the nose and throat; but this in turn causes rebound congestion and stasis and more risk of secondary infection.