Writing a biography? The first thing to decide is whether you plan one of a temporarily popular figure such as Benjamin Franklin which will haunt you the rest of your life from the Entertainment Books section of the used book store, or whether you plan a slightly academically-tinged highbrow biographies about a timeless yet forgotten figure such as Benjamin Franklin which will haunt you from the Biography section of the same store. I'll start with the second, coming back around to the first after a short photographic-tour holiday.
You have to decide how to provide references and whether to include footnotes --- so called because they resemble a pinky toe run over by a cartoon steam roller --- each 45 words, or use endnotes. Footnotes look nice and academic with numbers hanging all over your sentences, but they make it easy for people to check when you just made up your reference, marked traditionally by ``Ibid''. The advantage of endnotes is each of their pages counts as half a page toward getting your page count high enough. Plus you can use the kind where you list a page number, three words of a sentence, and then a term like ``Papers (485)''. With that style it's almost impossible for the reader to remember what she or he was looking up.
It's never easy to say just how long the biography you write should be, but to make the respectable kind eligible for prizes it should be at least ten pages for each year of the subject's life, or 532 pages, the winner to be decided in a best-of-seven contest. This may be challenging if the person wasn't actually interesting for all of those years --- of course, how interesting is a person supposed to be when they're five years old --- but you can make up any shortfalls with a section at back listing every book you ever read.
The introduction should have only a slightly defensive tone, asserting the subject is worthy of a new biography despite the (select: enormous or tiny) number of already existing biographies. Hint at the existence of documents you've been examining for the first time which shed new light on everything. Also explain that you don't mean to bring any particular agenda but will let the facts fall where they may once you've found them. After they do fall dust the shelf under them. There's no telling when the next biographer will be around although probably that one's book will be published the same month as yours. Conclude by thanking at least twenty people, no less than ten of them people you know.
The text should begin by describing the most interesting thing the subject did, starting from dawn and including what the weather was like and establishing the existence of cities or of weather. Stop just before the subject actually does whatever it was, of course, so the readers know they have to skim ahead to page 430 to learn that the subject actually did the interesting thing she or he was famous enough to get a biography written for. If you can't decide on something that was interesting, describe the subject's funeral.
Next comes the tracing of ancestors. The farther back you go the better your chance for a prize in biographic writing. You only have to identify the line of direct male ancestors. (If writing about Franklin Delano Roosevelt, since the first Roosevelt to do something interesting was Theodore, you may write about the Delanos instead, briefly.) Describe whatever information you have on hand about their being born and fathering the next male ancestor, as this warms you up for the real biography. Sometime around the grandparents you can start writing about the female ancestors. The objective is to make sure the subject of the biography doesn't even get born until at least a hundred pages in. The more readers who forget who they're reading about the better. Don't be afraid to include the Shinmiyangyo War if that helps the page count.
After that you just need to assemble the events of the subject's life into a coherent narrative and write it in a compelling manner. Wasn't that easy?
Trivia: On 24 October 1929, General Motors dropped from 60 to 53. Standard Oil dropped from 77 to 68. United States Steel lost six points; AT&T lost 18. Source: Anxious Decades: America in Prosperity and Depression, 1920-1941, Michael E Parrish.
Currently Reading: San Francisco Is Burning: The Untold Story Of The 1906 Earthquake And Fires, Dennis Smith.