For a number of years, I have been reluctant to use turnitin for much other than the occasional "plagiarism check" -- that is I would upload a paper here and there, now and again, just to see if a student had copied. Now, however, with improvements to the interface AND the rich "mark-up" features, turnitin.com has become a vital part of my teaching.
Each essay that I assign, now, has a "window" of completion -- that is a one week (or more) period for open submission via turnitin.com for any given assignment. I state clearly that essays are due on X date and may be uploaded with out penalty for lateness until Y date. I mention this policy in class with the caveat that I do not accept late work. (Here's a link to a Google Doc that explains my rule.) Turnitin is immensely helpful in this setting, as the system allows students to upload "on their own time." Also, if I am feeling particularly ambitious, I can read any student submissions DURING the submission window in order to get a "leg up on grading."
I will skip any lengthy discussion of the technical aspects of turnitin, and point the interested teacher to their help files and extensive support information. I will offer, however, that the ETS grammar checker coupled with GradeMark and the vast database of essays for plagiarism checking makes this service nearly indispensable.
Before I ask students to log-in to their turnitin.com accounts, I show this Slides presentation on the classroom projector, and I pause and clarify the different screens they will encounter in turnitin.com and their functions. I also distribute index cards that will serve for a "ticket out" to the lesson.
Once I feel that they have a handle on how to use the interface, at least in a rudimentary way, I ask them to log-in and read my feedback on their papers.
I circulate around the room to make sure they are looking at both the "purple" and "blue" comment marks. As a quick "check for understanding," I ask them to call me to their workstation when they have discovered a "purple" mark that is incorrect -- the ETS Rater System is not perfect. Once I verify the student is correct that ETS is incorrect, we delete the comment.
After everyone has had a chance to read his/her individual feedback, I distribute this extensive Google Doc guide (or key) to my comment set. The guide assists them to know what my marks mean in a full and complete way.
Once students have had a chance to read my "key," they must write on the index card three specific things they will improve upon for the next essay, based on my feedback to them. I collect the index cards as they leave the class.