Line Editing shares similarities with copyediting and many editors don't distinguish between the two. Line editing looks at the manuscript at a paragraph level and, like copyediting, the focus is also at sentence level and word level. A line editor checks for clarity, paragraph development and flow -- are ideas developed logically, does one paragraph connect to the next -- punctuation, consistency, formatting, paragraph and section breaks . . . line editing starts to get into the nitty-gritty of a manuscript.
My edits are thorough but not judgmental. A completed edit can discourage any writer; all you see is the markup. All you see are the errors. All the feelings you had in school when the teacher handed back your paper covered in red pen marks come flooding back. I try to alleviate those feelings by pointing out positives—a nice turn of phrase, for example. Comments are written to provide constructive feedback.