To prevent Norovirus and other infectous diseases, the best thing you can do is to wash your hands and gargle!
Wash your hands... You don't want to look nor feel like this guy
You must get into the habit of washing your hands at least 10 ~ 15 times a day; every time you go out of the house or the office and come back inside, you should wash your hands and gargle. Of course, wash your hands and gargle before eating. Wash your hands and gargle before going to bed at night and immediately upon waking in the morning.
Heck, wash your hands and gargle before you wash your hands and gargle and then wash your hands and gargle after that.
Seriously, I wash my hands about 20 times a day and, still even with that, I have gotten Norovirus twice.
I have it right now.
Norovirus only lasts a day or two, but it feels like Mike Tyson punched you in the stomach. The stomach cramps from Norovirus are very painful!
This is what Norovirus feels like
So, take my advice: Get into the habit of washing your hands and gargling after going out and touching anything...
Now... After writing this short blog about Norovirus, I need to wash my hands. I recommend that you do too.
Norovirus on Wikipedia: http://en.wikipedia.org/wiki/Norovirus