You'll need some background information about the person (Where he or she grew up, how old, perhaps other information. How much of this information you use depends on your subject. Most important, what about this person would be interesting to others? This should be the focus or theme of the story. It could be a particular challenge the subject has had to overcome, a success, a failure, an unusual view of life, or an activity that sets him or her apart from others.
How you start depends on what your interview subject says. You might use an anecdote--an interesting little story about life here, or at home, or about unexpected changes.
It could be a question, a bit of description, a quote, a contrast or any other device that will attract readers and get you into the story.
See Chapters 9 and 12 in Zinsser on The Lead and Interviewing.