Being a writer is highly individual, mysterious and personal. No one can make you into a writer but yourself. HOWEVER, you can be taught many things ABOUT writing. A professor of literature can bring alive an obscure classic for you, open your eyes as to how it works for the reader, and this may inspire you to experiment in your own writing in ways you haven't attempted before.
An attentive reader can share with you what she finds interesting in your manuscript — what she finds thrilling, boring or confusing, or just plain unconvincing — and that may teach you a great deal.
Other writers may offer advice and share personal experience; and that might help and then again it might not. What works for Stephen King or Elmore Leonard, for instance, really does not work for me.
And whenever your risk your work in the hands of a teacher, critic, beta reader, etc. BE SURE to seek more than one opinion, many more perhaps — especially if the criticism simply doesn't ring true. Be prepared to ignore the most heartfelt rejection.
Bottom line? We make ourselves into the writers of our dreams through faith in what we love, skepticism about criticism that doesn't help, and by ignoring advice which is not productive. It gets down to individual will, doesn't it? Trust in oneself.
I took the manuscript of Interview with the Vampire to a writers group early on. I had been invited to come. A person read aloud the first thirty pages. I then heard the members of the group weigh in. If I had taken to heart the responses of that group, I might have thrown the manuscript away. I didn't. I didn't hear anything there that helped. The thing I remember most was an utter lack of enthusiasm for the premise of the novel. "How far can she take this?" they asked. I thanked the group and I moved on. You have to do this. You cannot be at the mercy of all those who "don't get it."
When New York editors send back the work with faint praise or damning comments on genre, just ignore this and keep going. Keep seeking the editor who will "get" what you're attempting to do. Or publish on your own.
Remember there are no "pass or fail" grades for a novel. It's an individual creative act. And it is entirely possible to encounter people who hate what you do, tell you you have no talent, people who sincerely suggest you give up on writing because you have no natural gift for it — and to go right on past those people to become a successful internationally known writer. I know this, because I did.