I would recommend that you prepare your resume (or CV, preferably) to have available at the time of your interview. I would also recommend that you have two to three professors' recommendations to bring with you. Even if you have not had any prior teaching experience, some of your former professors may have recognized your teaching ability and be willing to note this in their recommendations.
I would also leave you with this piece of advice: be humble and honest with your interviewer. This person will be as interested in the quality of your character as in the content and quality of your prior education and teaching experience.