Work out, simply!
Have you noticed that the most physically active and fit people you know never seem to get sick? They appear to breeze healthily through cough and cold season with nary a sniffle, and what's worse, they tell you it's because they're so darn fit.
Why? While the study itself didn't investigate the metabolic reasons for the association, previous work hints that exercise, especially moderate exercise, can increase circulation of the body's sentry immune cells whose job is to patrol the body and nab any potential viral or bacterial invaders. Thus having the most efficient immune systems that were able to effectively recognize and eliminate viruses and bacteria.
So if you want to avoid a cold this season, you're going to have to work for it.