To start the internship, it is important to have contract signed between the student and supervisor. This will be great way to specify job responsibilities and policies for both sides. Another good idea is to keep communications open to ensure that expectations are met. Both student-intern and the supervisor should keep journals to document the work done and the hours worked.
As a possible supervisor to a student-intern, I will offer a project and help the student to complete it. I will ask the students to submit self-evaluation for their completed portions and will set up time to discuss with them areas for need of improvement.