I need some suggestions on questions to ask in an interview. Ya know how they always ask you if you have any questions at the end? This part is always difficult because I don't want to ask a question that might seem silly or make me look like I haven't done my research. I know the types of questions will vary from job position to job position, but what are some general intelligent questions to ask?

Also, any words of wisdom or advice in preparing for and presenting oneself during an interview? I've made to round 2, and I really want to do well. It's a city job.