Ask the artists how they place themselves within the larger world of hip-hop. This is important because you want to get an idea of what the independent hip-hop artists think about the current state of hip-hop and the ways in which they're adding new insights to the business.
Discuss any unique or unusual aspects of the artists' lives. For example, if you're interviewing an artist who was a former schoolteacher, he would tell you what made him want to pursue hip-hop as a career. The artist may view hip-hop as a way to reach the youth on a much broader scale than in the classroom.
Ask about solutions to some of the problems facing the hip-hop industry. You may want to discuss how hip-hop artists can be better role models to the communities they serve by being more mindful of the harmful effects of glamorizing the drug culture and violence and how this influences children.
Read articles on the artists before the interview. This keeps you from asking repetitive and dull questions that waste yours and the artists' time. It also gives you more time to have a productive interview where you can learn new things about the artists.