I posted this a while ago. But thought it worth posting again.
Grammatical knowledge or technique – the ‘hardware’ of editing – represents only part of the whole process. Editing is not entirely about objective analysis; subjective preferences play a role as well.
For instance, some editors loathe certain treatments of words. United States or USA or U.S. or US are just different styles; all are correct, but most editors will have a preference. Of course, a personal preference will be secondary to an existing publishing company’s house style. I have a prejudice against the em dash – I prefer its more dashing cousin: the en dash!
Then there’s the ‘inner ear’, a subtle skill that comes from experience. I think of it as the syntax or cadence that language possesses – it has its own soothing rhythm that an experienced ear is attuned to. A good editor will instinctively ‘know’ that there’s a missing beat and they’ll recommend ways to find it.
Not to be ignored, an editor will always embrace the fact that the book is the author’s ‘baby’. Recommendations need to be gentle in delivery but firm in reasoning.