It always comes down to subjectivity. It always does. I went to a writer's convention a little while ago where one of the writers said it helps if you can get a mentor to read over your stuff. Someone who knows what they're talking about. It was easy for him to say, though, as he had bloody Ramsey Campbell as his mentor. He also suggested getting a lecturer from an English course to act as one. Again, that's easy to say as he was a teacher.
What about those of us who don't know horror writer legends or teach English? Or studied English at a higher degree and therefore have the ability to ask someone? I am lucky enough to have some fairly litarate friends with sound judgement. However, those same friends are highly unreliable so I can't count on them to help me go over stuff. Which is fair enough since some of them are either busy writing their own magnum opus or, er, on the dole. Hmmm.
Also on my mind: ambiguity in writing. But more on that in another post.