We've been hashing out editing policy here for a long time now. It's pretty optimistic to think that people who are new to editing (let alone to SO/SE) will somehow 'know' how things work. It would be good to have one question that we can point them to.
(My idea is that the CW answer here could form the basis for a "How to edit" text along the lines of "How to ask a question" and "How to answer" that is shown to new users.)