#1 Wash Your Hands
Most cold and flu viruses are spread by direct contact. Someone who has the flu sneezes onto his or her hand and then touches the telephone, the keyboard, a kitchen glass. The germs can live for hours only to be picked up by the next person who touches the same object. So wash your hands often. If you can't get to a sink, rub an alcohol-based hand sanitizer onto your hands.
#2 Don't Cover Your Sneezes and Coughs With Your Hands
Because germs and viruses cling to your bare hands, muffling coughs and sneezes with your hands often results in passing along your germs to others. When you feel a sneeze or cough coming, use a tissue, then throw it away immediately. If you don't have a tissue, cough or sneeze into the inside of your elbow.
#3 Don't Touch Your Face
Cold and flu viruses enter your body through the eyes, nose, or mouth. Touching their faces is the major way children catch colds and a key way they pass colds on to their parents.
#4 Do Aerobic Exercise Regularly
Aerobic exercise speeds up the heart to pump larger quantities of blood; makes you breathe faster to help transfer oxygen from your lungs to your blood; and makes you sweat once your body heats up. These exercises help increase the body's natural virus-killing cells.
#5 Eat Foods Containing Phytochemicals
"Phyto" means plants, and the natural chemicals in plants give the vitamins in food a supercharged boost. So put away the vitamin pill, and eat dark green, red, and yellow vegetables and fruits.
#6 Don't Smoke
Statistics show that heavy smokers get more severe colds and more frequent ones.
Even being around smoke profoundly zaps the immune system. Smoke dries out your nasal passages and paralyzes cilia. These are the delicate hairs that line the mucous membranes in your nose and lungs, and with their wavy movements, sweep cold and flu viruses out of the nasal passages. Experts contend that one cigarette can paralyze cilia for as long as 30 to 40 minutes.
#7 Cut Alcohol Consumption
Heavy alcohol use suppresses the immune system in a variety of ways. Heavier drinkers are more prone to initial infections as well as secondary complications. Alcohol also dehydrates the body -- it actually causes more fluid loss from your system than it puts in.
If you can teach yourself to relax, you may be able to rev up your immune system. There's evidence that when you put your relaxation skills into action, your interleukins -- leaders in the immune system response against cold and flu viruses -- increase in the bloodstream. Train yourself to picture an image you find pleasant or calming. Do this 30 minutes a day for several months. Keep in mind, relaxation is a learnable skill, but it is not doing nothing. People who try to relax, but are in fact bored, show no changes in blood chemicals.
BONUS: How Colonics can help
A clean colon - clear of the excess mucous -encourages the colonization of beneficial microflora, which strengthens immunity!
Resources: WebMD: http://www.webmd.com/cold-and-flu/11-tips-prevent-cold-flu