Just let them know you are a Journalist, and writing for an influential media. don't ask them anything special. in fact, they will tell you what they think you need to hear, the most important thing according to them.
what +Asgar Mahmoudi
said is of great importance. that the thoughts, responses and reactions that you will face will be quite different. that's why i would suggest to talk to a lot of people to get a realistic glimpse of our current status of mind. talk to young generation, old citizens, beard men, guys wearing the modern fashion, students, business people, quality people, women wearing nice Hijab, and those who look different as well, kids even!
don't go back with "opposition is everywhere" or "hardliners! that's the way i'll describe Iranians".
don't get into controversial issues if you are not in the mood to hear all their answers + no matter which side they will advocate, most likely you will find everybody quite freindly and willing to talk. if you ask me to point out only one thing they all share, that's hospitality. good-luck.
thanks for mentioning +Hassan Al Shouli