In 2000, NPR’s listeners voted Al Green’s 1971 hit “Let’s Stay Together” one of the 100 best songs of the 20th century. With its plea for two people to hang in there, whether times are good or bad, it quickly became an anthem for lovers. But it was what Green learned about delivering a song that made this one work and gives us some clues about our own path to greatness. By the time he was 20, Green had already formed his own group, the Soul Mates, who scored a minor hit wit