It's nice to see several of you say "rest" and "stay home" as part of your strategy. I wish more people implemented this as part of their means of getting better. It's one of my biggest pet peeves when people who have no business being out in public do so when sick. It's one of the big reasons why things spread as quickly as they do. No one likes being sick. Just because you have already gotten it, doesn't mean you shouldn't care about others. I always see or hear people say "I can't miss work, I need the money." In some cases, this is actually true. But, I have seen so many others where people blow their sick days when the weather is nice because they want a long weekend or to be lazy. There's a reason they're called sick days. Use them when you are sick so you can stay home and not spread what you have to everyone at your job, or on the bus, subway, etc. If you can't bank them and you're getting close to them expiring because you stayed healthy the whole year, use them then to take a long weekend.
My strategies for prevention are simply making sure to get 8 hours of sleep a night, eat well balanced meals, drink a lot of water, use a saline nasal wash to keep the nasal passages clean and moist, avoid people who I know are sick the best I can, take a good quality multi-vitamin, elderberry, and astragalus. When the season really starts to pick up/get more severe (December-March) I'll double my typical vitamin D3 intake and add North American Ginseng.
If I do come down with something, I stay home and rest, keep eating well, increase the elderberry and water, take Umckaloabo extract at the first sign of symptoms, inhale steam infused with oregano oil, gargle with salt water and goldenseal if I have a sore throat.