Ideas don't spring fully grown out of the minds of creative people; they favor minds cultivated by research. It's an open secret that the investigative skills of "creative writers" match those of "scholars."
Of the activity that led to composing "Spillane," mystorian and jazz musician John Zorn notes:
Because I write in moments, in disparate sound blocks, I sometimes find it convenient to store these "events" on filing cards so they can be sorted and ordered with minimum effort. After choosing a subject, in this case the work of Mickey Spillane, I research it in detail: I read books and articles, look at films, TV shows, and photo files, listen to related recordings, etc. Then, drawing upon all of these sources, I write down individual ideas and images on filing cards. (1987: 9)This assignment requires you to follow suit, to follow Zorn's lead.
Investigate the life and work of the figure you've chosen to focus on in your docu-novella, but instead of submitting the results of this research on index cards, draft a narrative that describes (in, perhaps, an ideal way) your investigation. The form of this story might derive from your object of study. For example, Spillane might suggest a detective story, Anne Frank might suggest a diary, St. Paul an epistle or open letter, Freud a case study. At the end of your story, include a complete list of the sources--an inventory of the texts and graphics--you've discovered. Gather data--a dossier--sufficient to create, at a later date, a chronology of your subject.