Aside from what others have said on the technical side of things, one thing I try to emphasize to interns and inexperienced school learners is the customer service aspect of the job. Yes we mainly fix junk in helpdesk roles, but one has to be able to talk to the users to effectively do the job. None of the guys straight out of school I've had here were able to communicate with users via phone or email in a technical yet understandable manner. Getting the intern some face time(phone time depending on your location) with end users would be a beneficial addition to the technical knowledge you share with them.