There is something called a Neti Pot that absolutely WILL shorten your recovery time. If you use it when you first start feeling stuffy, you can sometimes circumvent getting sick entirely. I am using during my pregnancy to relieve pregnancy-related stuffiness. I also started getting a cold and used it to keep from getting sick. People with allergies also use it to flush pollen and other allergens from their sinus passages.
It's essentially a small pot made to fit your hand with a long spout. You buy non-iodized salt to use with it. Follow the directions on the box, but to give you an idea, you mix a small amount of salt into warm water and put the tip of the spout into one nostril, tip your head to the side and allow the water to flush out your sinuses. You will not get it right the first time and the water will probably run down your throat. Bring your chin forward and breathe through your mouth. The water will go in one nostril and run out the other one. Yes, it's totally gross and feels at first like when you accidentally inhaled pool water, but it's about 1 minute total of discomfort, compared to days or weeks of feeling sick. You can flush up to 4 times a day if you need to. Go on YouTube to find some demo vids.
Neti pots are $10-$15 and you will wash and reuse it over and over. It may come with the salt in a little kit, or you can buy the salt separately for $2-3. Just make sure it's non-iodized. Don't use table salt - it's typically iodized. You can find Neti pots in health food stores or even CVS and other drug stores like them, sometimes in the market, too.
The way it works is that because it flushes your sinuses out, the bacteria (or allergens) go, too. You rob the bacteria that are making you sick of a place to breed. Your body then only has to fight off the little bit that's left instead of a constant supply of new bacteria. I flush, then take a nap, and am usually as right as rain the next day.
As always, drink plenty of water and take your vitamin C. If you're taking chewable C, brush your teeth after - the acid can harm your tooth enamel over time. The best thing you can do is sleep. Your job - Neti flush, drink water, sleep.