The key to producing any effective piece of writing is in managing readability; technical proficiency is important, but things like flow and structuring problems are often the death of many works which are otherwise 'technically' correct. Catching grammar problems and suggesting alterations is an important step, but it is only the first. As an editor I pride myself in maintaining communication between myself and all of my clients; often a press to clarify or reconsider phrasing is far more helpful than simply prettying up an unclear or confusing section. My experience is rather broad: I have worked on many academic papers, dissertations, and theses as well as on several textbooks, websites, and novels.I would love to help you with yours.