I usually use hot tea instead of just hot water. A bit of honey and lemon and Crown Royal (regular or peach flavored).
I once caught a horrendous cold while at WDW and on our last day the bartender at ESPN suggested I have a hot toddy. It worked better than any cough syrup. Now I swear by hot toddies and gluhwein (had some of that in the Germany pavilion on the same trip with similar results) when I have a cold.