Practice it in your family. Enlarge it in your friends. Share it with humanity. The secret is to wear it as a mask for your problems. It might surprise you how many others do the same thing.
Common sense covers it just about as well as anything.
You don't have to fight to be brave. Millions of good, fine, decent folks show more bravery than heavyweight champs just by getting out of bed every morning, going out to do a good day's work and living the best life they know how against the law of odds. Keep the word handy every day of your life. But it is the inside that counts and don't ever forget it. With Him, life can be a beautiful experience.