Research the company and the job position you are applying for:
Write down any questions you may have about either so you can ask during the interview. If there any requirement of the job that you are unsure of, you should definitely ask during the interview. It always looks nice when you go into an interview with intelligent questions. It shows you put effort in preparing for the interview. However, never ask questions just to ask questions. The interviewer will see right through that. Your questions should be genuine and relevant.