Plan your story:
What is your story?
Who will you interview?
What are your questions?
Write how you will ask to interview your person.
How will you find additional information? Internet? Another person? a student?
Remember the Interview Tips and directly after your interview, go some place quiet and write up your draft, SO you won't forget and IN CASE you need to ask for another interview. You will forget things -- your notes will not be enough, so directly after your interview, go some place quiet and write up your draft. It's that important.