We’ve all heard of people who never seem to get sick while everyone else comes down with the cold or flu. How do they do it? Steal their immunity-boosting secrets by following these simple tips for reducing your risk of getting sick.

For starters, health experts recommend washing your hands — with soap and warm water for about 20 seconds or longer — periodically throughout the day. Use alcohol-based hand sanitizers when soap and water are not available. Getting a yearly flu shot, which exposes your body to dead flu viruses so it builds immunity against them, is one of the best things you can do to avoid influenza each year.

Sleep, Eat, and Drink to Prevent Colds

"The most important things in terms of improving immunity are rest and good sleep," said Dr. Ronald Stram, founder of the Center for Integrative Health and Healing in Delmar, N.Y. While individual needs vary, most experts recommend at least seven hours a night. A healthy diet is also vital. Nutritionist Lona Sandon says the best foods for supporting immunity come from Mother Nature.

For immune system health, "Research shows that a whole foods approach is best," said Sandon, an American Dietetic Association spokeswoman who recommends a diet packed with whole grains, vegetables, and fruits. That's because, for normal people without severe vitamin deficiencies, taking extra vitamins, supplements or herbs has never been shown to lower the risk of developing an infection.

Foods like oranges, kiwi, pineapple, and colorful peppers are packed with vitamin C, which helps your body produce infection-fighting antibodies, Sandon says.

Most fast food, on the other hand, offers little nutritional boost. A lack of key nutrients could mean the difference between getting and avoiding a cold. If a little vitamin C is good, then a lot is better, right? Not necessarily. With the exception of people who are subject to extreme cold or extreme physical activity, large doses of vitamin C do not appear to lower risk for the common cold or other illnesses.

Protect Your Skin and Stay Hydrated

Vitamin A helps keep skin and mucous membranes in the nose and mouth healthy, so they can act as a protective barrier against bacteria and viruses. Sources include orange, red, yellow, and dark green fruits and vegetables as well as liver, said Sandon.

Other nutrients that support immunity, Sandon says, include vitamin E, found in whole grains; selenium, found in many plant and animal foods (levels vary depending on selenium levels in the soil); and zinc, contained in foods ranging from whole wheat bread to lean meats, milk, and yogurt.

Staying hydrated is key, Stram says. Most people need half an ounce of non-caffeinated fluids for each pound of body weight daily to maintain proper hydration, most, if not all, of which comes from the foods we eat. This keeps mucous membranes moist, which lowers the chance of a cold or flu taking hold in your nose or lungs. Avoid sodas and other heavily sweetened drinks; the added sugar has little nutritional value.

Avoid Stress to Avoid Colds

"Serious stresses do influence the immune system," said Frances Cohen, a psychologist at the University of California, San Francisco.

Since stress is unavoidable for most of us, Dr. Cohen suggests that people adopt coping methods or, when appropriate, find ways to exit stressful situations.

Moderate exercise (30 or more minutes a day, according to the American Heart Association) bolsters immunity and reduces stress, while hobbies and spending time with friends can improve well-being and ease worries.

To manage stress, Cohen advises viewing situations from a different point of view or taking time to enjoy beautiful scenery or art. "I think of it as putting on a different pair of glasses," she says. This can help you gain perspective on things and stay healthy, both physically and mentally.