Punctuation has purpose, spelling says something, and conventions convey meaning. But editing is more than what your English teacher did with a red pen.
What kind of editing do I need?
Different writing projects need different levels of shaping. It helps to understand the spectrum of editing services.
Developmental editing is big-picture, structural help. When I conduct a developmental edit, I typically read over a large chunk of text before offering any suggestions. At this stage, whole sections might need to be moved, deleted, or written. I can help you see the overall shape of your manuscript, whether it's a novel, memoir, website copy, dissertation, personal essay, short story, or something else (but not poetry. I'm terrible at poetry). I'll provide detailed suggestions, as well as ask you pointed and guiding questions, in the form of embedded comments in a Word doc. My developmental editing rate is $150/hour.
Line editing is word and sentence work. Once I have read a sufficient passage of your manuscript, I pick up on your voice, tone, and purpose. Then I remove or revise anything that interferes with your voice and style. Often this means deleting extra words or rephrasing things so fewer words are needed. It also means addressing interruptions to flow and making things clearer by cleaning up syntax. Finally, it's fixing punctuation, usage, spelling, and grammar, and capitalization. My rate for line editing is $90/hour.
How do I know which one I need?
Most people, unless they have been writing a long time and/or have already created several drafts of their manuscripts, first need a developmental edit. Ask yourself these questions:
Does the manuscript as a whole have a satisfying structure with a clear beginning, middle, and end?
Do my chapters or sections make sense and have clear takeaways?
Is there a strong logical and rhetorical framework?
Have I fully developed all the ideas I want to?
Am I certain the only changes that would improve this piece are minor edits to individual sentences?
If you answered "No" or "I don't know" to any of the questions above, you probably need a developmental edit. If you answered "Yes" to all of them, you are probably ready for a line edit.
Why is there a price difference?
Developmental editing is intellectually more demanding than line editing. It requires an analytical mindset and an ability to hold several things in mind at once and move continually among them: the writer's goals, the audience's needs, and the writing's structure. It also requires creativity to solve structural problems and deep knowledge of how writing works to suggest new approaches and powerful revisions.
Many writers use me for both developmental and line editing. We go two rounds. In the first, developmental round, I provide suggestions and the writer revises accordingly. Then she resubmits the chapter or section and I conduct the line edit. Developmental editing has a higher rate but takes less overall time.
Lit Hub has a great article about the artistry of line editing.