An interview should be a two-way process. Yes they're interviewing you, but you also want the opportunity to interview them! Changing jobs isn't something you do every day, so you want to make sure that the role and organisation are as close to what you're looking for as possible. The best way to do this is to ask for clarity on areas that you've got some queries on and then weigh up their responses with everything else you know.
It's also really important to have questions ready because it shows you've spent time thinking about the job and want to know more.
Here are some suggestions, but you'll obviously have your own based on what you want to know
Is this a new position and if not, why did the person before me leave the role?
What are your expectations of the successful candidate during their first 3 months in the role?
Can you give me some idea of a typical day or what percentage is spent on xxx and xxx, plus are there are responsibilities not mentioned in the position description?
How would you describe your company culture?
What makes an employee successful in your organisation?
What do you personally like about working for ABC Company?
Can you tell me a bit more about the team and how my skills/experience would fit into it?
How do you help your staff grow professionally - do you offer training?
What's a typical career path for someone in this role?
You'll probably only have time to ask 2 or 3 questions but may only get chance to ask one, so decide beforehand which you'll choose if you're in that situation.
If you find that all your questions have been answered during the course of the interview, then it's best to respond with something like "thank you, I did have some questions ready, but you've answered all of them during our conversation" rather than just saying "no"!
Finally, before you leave, always remember to thank the interviewers for their time and ask them to confirm the next steps in the process.