Zinc gluconate (20 mg every 2-4 hours)...it worked for me last week during midterms. I basically had that 'gonna be sick' feeling for 5 days. I experienced no symptoms during those days and it went away just like that. No real discomfort, everyone on my residence floor was suffering from that cold. I think it inhibits viral activity, so the virus can't reproduce as fast as it normally would (leaving it without a fighting chance against the immune system). Remember though, the zinc has to be taken before the onset of symptoms otherwise its useless (the virus had enough time to reproduce a fuckload of itself). Studies are inconclusive on this however, but it worked for me. Careful of copper depletion, zinc tends to displace it.
Heavy training might suppress your immune system for a short while...also training while sick sucks.
Don't use vitamin C if you believe the pathogen is bacterial. I'm not sure about that though...I learned that in physio, one of Linus Pauling's debunked theories.
So in short, ZINC GLUCONATE. All the other stuff suggested seems good & wouldn't hurt.
Good luck!
Edit: to clarify, the 'gonna be sick' feeling is that weird metallic feeling in your throat accompanied by soreness. It feels nasty.