I'm a big fan of better living through pharmaceuticals, so I treat symptoms with over the counter meds as much as I can (but buy single ingredient meds rather than multi-symptom ones so you're not getting unnecessary drugs). I start them early if I feel a cold coming on.

Relieving any cough or congestion and being able to comfortably rest goes a long way towards feeling better. Talk to a pharmacist if you're not sure what to get, they know a lot about OTC meds as well as prescription ones.

As others have mentioned, fighting a low-grade fever is sometimes counter-productive. If I'm not feverish, I even like to soak in a hot bath to get my body temp up. If I'm running a fever, I'll bundle up with blankets as much as is comfortable. Drink a lot of water, Gatorade, or OJ to stay hydrated and keep an eye on your temp so you can get help if the fever gets too high.

Other than that I try to sleep as much as I can.