Use a humidifier: Humidity adds moisture to the air which will in turn moisten your skin (including nasal passages) and thin some of the mucous in your sinuses. This makes it easier for you to breathe and easier for the mucous to drain. We just boil a big pot of water for the same effect since we don't own a humidifier.
Wash your hands often: this won't necessarily help you once you've got the flu, but it will help you from spreading it. Also try avoid sharing any towels in the house and use alcohol hand sanitizers on surfaces like door handles, faucet handles and kitchen surfaces.
Be sure to get a little sunlight: studies have shown that vitamin D, not vitamin C, provides the most efficient protection against cold and flu viruses; it only takes 20 minutes in the sun, with the hands, arms and face exposed, to get a healthy dose of Vitamin D.
Wear socks: it took me forever to give into this recommendation, but now I realize it's so important to keep your paws warm, whether you're sick or not. I also keep a "sick hoody" for putt-putting around while hacking and sniffling.
Keep tissues readily in reach: we have tissue boxes everywhere throughout our apartment. We personally endorse Puffs as the softest brand.
Chicken soup, Zicam, Emergen-C, and medication all trumped by sleep: be sure to have a room where you can fully block our the lights to get some rest. Because nothing is more important in helping you regain your help than sleep (but be sure not to give into the wive's tale of starving a flu...eat!).
Lastily, my girlfriend and I have a tradition of having some tawdry celebrity magazines around when we're sick (because our heads are usually way to foggy to deal with anything beyond the offerings of US Weekly or InStyle) and a movie rental or two via Apple TV or Netflix to keep us preoccupied while being bed/couch bound.
Do any of you out there have particular home habits or advice when sick?