Before they were published, many great writers tried and failed. Even if you're an amazing writer, you'll still be receiving much criticism and rejection before and after you are published: from publishers, from your audience and from reviewers.
Having read a lot of books — classics and modern — I see a lot of common mistakes pop up in people's writing. I also see a lot of things which make an author great. Hopefully, my experience can be of use to you.
As always, if you're interested in a collaboration or guest writing, please contact me.