Whether you are editing someone else’s writing or they are editing yours, you need to know your editing marks.
These are the most commonly used marks:
Another good list of editing marks:
Get it here.
Another fine resource:
1. Share your writing with a fellow author.
2. Edit your colleague’s work. Have them edit your work.
3. Examine the suggestions your colleague/editor has for you.
4. Remember, you decide if you wish to make any changes to your manuscript.