I have made it a rule in my home that whoever (including me) catches flu will literally announce it. And after letting everybody know, s/he will volantarily separate daily use items: towel, soap, bedsheet, etc. I also do so while meeting friends, or relatives. If I am having flu, I even refuse (politely) to shake hand or sit near them. That's going bit too far, but doiing so, I am caring for them.
Another remedy that I have figured out is to keep anti-allergic tablet named "Antial" with me all the time.. So whenever I feel like I have started catching flu, I just take it. Most of the times, it saves me from actually giving into the allergy or viral stuff.