“Are you a tutor?”
Not exactly. I don’t use the word “tutor” because it implies someone coming over to your house, sitting down at the kitchen table, and being paid by the hour. A tutor is also an expert in a particular academic subject. His job is to explain the material and help the student master it.
Writing is not an academic subject, per se. Some knowledge is required to write well, of course. One must know the rules of grammar, usage, and mechanics—(I consider it my job to make sure my students learn the rules and follow them!)—but writing is mostly a skill.
To win a baseball game, it is not enough to know the rules. One must have quick reflexes, good hand-eye coordination, strength, agility, and speed. To give a breathtaking musical performance, one must not only know the notes, but demonstrate coolness under pressure, courage, and self confidence. This kind of mastery requires good coaching and, most importantly, practice. Same goes for writing.
A good writing coach helps you to develop your skills through practice.