From The Talent Code by Daniel Coyle

Another example is Ray LaMontagne, a shoe-factory worker from Lewiston, Maine, who at age twenty-two had an epiphany that he should become a singer-songwriter. LaMontagne had little musical experience and less money, so he took a simple approach to learning: he bought dozens of used albums by Stephen Stills, Otis Redding, Al Green, Etta James, and Ray Charles, and holed up in his apartment. For two years. Every day he spent hours training himself by singing along to the records. 

LaMontagne’s friends assumed he had left town; his neighbors assumed he was either insane or had locked himself inside a musical time capsule—which, in a sense, he had. “I would sing and sing, and hurt and hurt, because I knew I wasn’t doing it right,” LaMontagne said. “It took a long time, but I finally learned to sing from the gut.” 

Eight years after he started, LaMontagne’s first album sold nearly half a million copies. The main reason was his soulful voice, which Rolling Stone said sounded like church, and which other listeners mistook for that of Otis Redding and Al Green. LaMontagne’s voice was a gift, it was agreed. But the real gift, perhaps, was the practice strategy he used to build that voice.