The best IntroMinute I've ever heard is from Jennifer Yoxall. She usually dresses up or incorporates a song describing the person she introduces. It is exceptionally creative and very memorable. Weeks or months later, I can associate the individual she presented with a song or costume. Her InfoMinutes are often the first thing I think about when referring to the individual Jennifer introduced. 

I typically prepare for an IntroMinute by scheduling a coffee with the person I am introducing. I usually plan a virtual coffee if I can't make an in-person coffee. During the coffee, I take notes to remember important details about the person I am introducing. 

Typically my go-to question is, why did you pick your career? That question makes the person open to sharing more information about themselves, and I base my other questions on their response. Ultimately, this should be a conversation, not an interview.