The moment you hear a cough echoing through the hallway or notice the trash cans all filling up with tissues, you're typically on red alert for the germy culprit. Once one person in the office gets sick, the bug will almost inevitably make it's way around to you. Keep the cold at bay as long as possible with a few precautions.
First, and probably most obvious, is frequent hand washing. After using the restroom, before eating lunch, and after an encounter with the sick individual, be sure to soap up. When exiting a work the restroom, avoid the door knob if possible.