Eat a mostly plant-based diet
You don't have to give up meat entirely, but think of meat as a side dish and not the main course. Make sure your diet is packed with fruits, vegetables and whole grains. Avoid sugary, processed foods and fast foods. Limit your red meat consumption to no more than 18 ounces a week. Cut back on the salt and the booze.

Maintain a healthy weight
While a body mass index (BMI) of up to 24.9 is considered normal, keep your BMI between 21 and 23 and avoid gaining weight during adulthood for cancer prevention.

Exercise regularly
Find an exercise or sport you love to do and then do it. To reap the benefits, all you really have to do is walk briskly for at least 30 minutes a day while you limit sedentary activities, such as watching television. And if you're feeling particularly energetic, exercise moderately for 60 minutes a day or vigorously for 30 minutes for even greater cancer protection.

Don't smoke and avoid secondhand smoke
Not only does cigarette smoking cause 87 percent of lung cancer deaths, but also it is responsible for most cancers of the larynx, oral cavity and pharynx, esophagus and bladder. In addition, secondhand smoke is responsible for an estimated 3,000 lung cancer deaths annually among U.S. nonsmokers. Tobacco smoke contains thousands of chemical agents, including over 60 substances that are known to cause cancer. While the risk of developing smoking-related cancers, as well as noncancerous diseases, increases with total lifetime exposure to cigarette smoke, stopping smoking has major and immediate health benefits, including decreasing the risk of lung and other cancers, heart attack, stroke and chronic lung disease, according to Cancer.gov.