Narrow your search. You will achieve familiarity with your subject more readily if the subject was famous for something in which you yourself are interested. The famous black person might be famous for medicine like Vivien Thomas, for politics like President Barack Obama and Kwame Nkrumah, for entertainment like Ella Fitzgerald and Biggie Smalls, for military prowess like Jean Jacques Dessalines and Harriet Tubman, for sports like Wilma Rudolph and Michael Jordan, for philosophy like Franz Fanon, or writing like W.E.B. DuBois and C.L.R. James, or for any number of other things she or he did. Search the internet or the library using the terms "African American," but also "Pan-African," and the names of countries where black people predominate, like Nigeria or Haiti, and using terms for historical phenomena like "Reconstruction" that feature black people.
Identify a specific topic or event about that person if you are not simply doing a biographical overview. Instead of just President Obama, you might focus on his childhood or his presidential campaign, or his family. Instead of writing about Harriet Tubman's entire life, you might focus on her adventures with the Underground Railroad or her later career as a public speaker for women's rights.
Make note cards recording pertinent individual facts as you do your research. Write down the fact and where you found the fact, so you can save time when you do your footnotes and citations.
Construct an outline. Unless it is required, don't bother with the old, formal Roman numeral outline. Draw a circle in the middle of your page. Write your topic inside the circle. Determine the three to five most important things pertaining to the subject. Draw lines leading away from your circle and draw circles at the end of those lines. Write those three to five main sub-topics inside those circles. Make a note card for each of the subtopics. Go through your fact cards, and place them in stacks under the most appropriate subtopic cards.
Write three to five paragraphs summarizing each subtopic, and using your facts. Determine if there is a sequence to the subtopics. Do they represent something that happened chronologically in time? Does one require an explanation first before another makes sense? Stack your subtopic paragraphs in the order you determine makes the most sense to a reader who has never read anything on the subject.
Write one paragraph that summarizes your entire essay. Then write one sentence that summarizes the entire paragraph. Now rewrite the introductory paragraph, using the one sentence as your topic sentence. The opening paragraph needs to tell what you are writing about and what the main points are.
Write the subsequent paragraphs in the order you established in writing your subtopics by combining them into sequential paragraphs, then editing ruthlessly to say as much as possible in a little space as possible, while still retaining the essential information. Remove editorial comments.
Take the draft to your adviser. Ask the adviser for any editorial advice. Take the editorial advice and rewrite. Write a concluding paragraph that sums up what you have just written.