1. Wash or sanitize hands often. Everything you touch at the office, the mall, in the club may have been touched by someone who just coughed in his hand or wiped his nose. Ewww.
2. Don't touch your face (esp. eyes, nose, mouth) when you're around a sick person, after shaking hands, or have been touching surfaces in a public place...like the door or the pen you just borrowed.
3. Don't smoke. Smoke irritates the airways, making you more susceptible to infection.
4. Don't share or re-use glasses/dishes/utensils if someone in your household is sick. Avoid cross contamination & reinfection.
5. Throw away dirty tissues after each use. Seems obvious, I know, but you'd be surprised how many stash a dirty tissue under their pillow or leave them in a pile next to the bed for someone else to pick up!
Now go wash your hands!