The (sadly, late) novelist John Gardner was, as well, a lifelong teacher of writing at a wide variety of universities and workshops. Oh, how I wish I could have studied with him, particularly after reading On Becoming a Novelist. His approach toward the new or "emerging" writer is one of profound compassion and encouragement, and there's at least one absolute gem on every page:
Occasionally, mean-spirited people have written good books, but the odds are long. [p.137]
Talk about writing, even in a mediocre community of writers...fills you with nervous energy, makes you want to leave the party and go home and write. And it's the sheer act of writing, more than anything else, that makes a writer.[p.77]
Novel-writing is not so much a profession as a yoga, or "way," an alternative to ordinary life-in-the-world. Its benefits are quasi-religious a changed quality of mind and heart, satisfactions no non-novelist can understand and its rigors generally bring no profit except to the spirit. For those who are authentically called to the profession, spiritual benefits are enough.[p.145]
Gardner also wrote The Art of Fiction, which is also well, well worth the read. (I blush to say I've only read one of his novels, Grendel, but I remember it being a knockout.)
You can find the True John Gardner Believers at www.johngardner.org and The John C. Gardner Appreciation Page. And if you, like me, are struggling with agonizing doubt about whether one truly has the writer's vocation (or, indeed, the writer's aptitude), you should definitely read On Becoming a Novelist. Therein, you will find that even asking these questions puts you well along the path.