Job Interview Questions: What are good questions to ask at a job interview?

It says everywehre online that asking questions at an interview is a good thing. It shows interest in the compant and makes a candidate seem better - however when I've had phone interviews / in person interviews in the past, whenever I've been asked if I have any questions, my mind will go blank.
So what are some good, diverse questions to ask? I have an interview for a sales job at a call centre if it helps. Many thanks :)

Job Interview Basics -- Best Preparation

Recommended Answer:
What is the next step in the hiring process?
When are you going to make your decision?
Can I call you?
Where do you see the company in 5 years?

3 Steps to a Great Job Interview

• Whats the perks,
  Whats he pay,
  when can i start,
  how many breaks there are,
  whats the hours a week,
  how flexible the job is,
  and why they are hiring. + more