* Who fascinates you? Who has a story that you find compelling and want to share?
* Is there a specific aspect of their life you want to explore? Maybe it's their career, their childhood, their struggles, their triumphs, or their impact on the world.
* Is there enough material available about this person? Do they have readily accessible primary sources (letters, diaries, interviews) or secondary sources (books, articles) that will inform your writing?
Once you've chosen your subject, you can move on to the next steps of research and planning.