You must provide background on your subject - their age, where they grew up and were educated, where they live now, are they married, do they have kids, etc. Also, who and what influenced them, their ideas, their choice of vocation or profession. Interview them in person so you can describe their appearance and mannerisms. Watch them at work. Talk to people who know them. If your profilee is controversial, talk to some of his/her critics. Remember, your goal is to create a true portrait of your profilee, warts and all. No puff pieces.