Correct vocal mechanics are essential. Without that foundation, you'll never be able to sing with physical ease and you will always be at risk for vocal damage. However, another essential part of the equation is artistry. Artistry encompasses several areas: You have to be able to tell the story, express the emotions of the tune and make your audience believe them. You need to take them on the journey along with you or you'll lose them before you've even left the train station. This can be broken down into many elements, some of which are stated below in the words of Ray Charles:
"With singing, the name of the game is to make yourself believable. When somebody hears you sing a song and they say, 'Oh, that must have happened to him,' that's when you know you're transmitting. It's like being a good actor. You make people feel things, emotions and whatnot. But you gotta start with yourself. You got to feel it yourself. If you don't feel it, how do you expect someone else to?" ~Ray Charles