Mastery of his craft should not be an obsession with the writer. But for him it is the sole means of creating a work. You can't be a musician unless you master an instrument. You can't go on being a musician if you give the instrument up. The gift of imagination is magnificent, but it is dead without the gift of speech, without the gift of the story-teller.
How to tell the story, how to write? That is the agonizing, crucial, vital, and terrible question which haunts the writer. Morning, noon and night, in every manifestation of his being, the writer keeps hearing this question about his art: how to write? One cannot imagine a writer indifferent to the form of his work -- such a man would be a freak, a monster.
Style has many components. The difficulty of mastering them is that they are devoid of absolute existence. Rhythm, melody, vocabulary, and composition do not live independent lives of their own; they are interconnected like chess pieces. Just as it is impossible to move a pawn without changing the position of all the other pieces on the board, so it is impossible to "correct" in a literary work the rhythm alone or the vocabulary alone without affecting the other components of style. When I cross out a word, I change the structure of the sentence, its music, its rhythm, its relationship with its environment.
But the basis and the soul of style is language. Language is the King on the chessboard of style. No language -- no writer. "If an author has no style, he will never be a writer. But if he has a style, a language of his own, then there's hope for him as a writer. Then one can discuss the other aspects of his work." So said Chekhov.
I too would like to write of the joys and despairs of eternal labour on words, on style -- the labour of the writer for whom literature is the business of life, an all-demanding and exacting calling. The writer's obsessive love of words is a source of suffering, but of suffering that he will never regret. (in Maxim Gorky, Vladimir Mayakovski, Alexei Tolstoy, and Konstantin Fedin on the Art and Craft of Writing 256, 257, Alex Miller trans., 1972).