Student's guide to writing college papers, Fourth edition - Kate L. Turabian 2010

Guard against inappropriate assistance
Preventing plagiarism
Writing your paper

Before experienced writers turn in their work, they often show drafts to others for criticism and suggestions, and you should too. But teachers differ on how much help is appropriate and what help you should acknowledge. Most instructors encourage students to get general criticism and minor editing, but not detailed rewriting or substantive suggestions. You usually aren't required to acknowledge general criticism, minor editing, or help from a school writing tutor, but you must acknowledge help that's special or extensive. Your instructor, however, sets the rules, so ask.