First, in addition to hand washing (which I did obsessively), I've heard that gargling with salt water and also swabbing out your nose with salt water can help prevent catching the flu.
Secondly, did I mention that it comes on fast. My suggestion is to have the following things already in your home just in case because once the flu hits you won't be able to go get them yourself and probably won't want to wait for someone to get them for you.
Tylenol for fever and achesYou will be ahead of the game if you also have a couple pair of your most comfy pajamas and extra clean sheets on hand.
A heating pad or rice bag (I spent a lot of time with my rice bag on to relieve muscle pain and a cold wash cloth on my head to keep the fever down).
Gatorade or something like it plus any other liquids you like to drink. I don't really like "sports drinks" but you will dehydrate quickly so consider them a necessity.
Crackers or pretzels - you'll need to try to get a little something in your stomach.
Jello - by day two this was a good option as both food and help in re-hydrating. It's also easy on the throat.
Hot tea - whatever kind is your favorite. This will help with the congestion, relaxation and re-hydration.
Chicken noodle soup - toward the end of day two or beginning of day three you will start feeling a little hungry. The soup is easy on the stomach and throat and helps with the congestion.
I am now exhausted from sitting up and writing this so I'm going back to bed. Hopefully you will avoid the flu, but if not, at least you can be prepared.