At the end of most interviews, the candidate is usually asked if he or she has any questions for the interviewer. The answer should be yes.
There are several tactics to ask a meaningful question. For instance, it is an opportunity to connect with the interviewer and ask them something like "What do you find most exciting about working here?"
Alternatively, you can use the chance to show off your ambition and ask something along the lines of "What are opportunities for training and career advancement?" This question also demonstrates that you are thinking of long-term commitment to the company.
If you haven't had an opportunity to demonstrate your familiarity with the company, you may want to ask about something you saw on the company's website that drew you to the company.
Ultimately, you want to make a great first impression and have a strong close to the interview so be prepared with a couple of questions.