Zinc lozenges work really well for lessening the length and intensity of a cold. They have the ones that are like cough drops now (cold eeze) which are super convienent. If you can find them at the drug store the zinc lozenges which come in a vitamin bottle work best.
My mother uses them and has not had a bad cold in 21 years!!! No kidding!
When you first start noticing the symptoms of a cold (dry throat, sneezing, sniffles, etc) you start taking them according to the instructions, or like one an hour for all waking hours for the first day. It is important to suck the lozenge and not chew it. I will warn you that though they don't taste bad they leave a nasty aftertaste and will make you super thirsty.
The zinc adheres to your mucus membranes and doesn't let the virus attach.
Airborne works really well too.