Keep Your Hands Off Your Face. Whether you’re nibbling on finger foods or you’re a nail biter, your hands have a habit of finding their way into your mouth, not to mention your nose, and eyes — all areas where germs can enter the body. And if you haven’t recently made it to a sink to scrub your hands, you’re inoculating yourself with those cold germs. To prevent cold and flu viruses, don’t touch “your eyes, nose, or mouth with your hands,” says Dr. Elder. And “encourage others not to touch their eyes, nose, or mouth with their hands — this is how germs get inside you” to grow into an upper respiratory infection. That will also help prevent cold and flu viruses from spreading.