Instead of starting the story chronologically, or making myself write preliminary matter before getting to the meat, I like to dive right in with a bit of the story that interests me and that I understand now. It doesn't matter what I don't yet know -- those things will come in time. What does matter is that I know one tiny piece of the thing, and that I feel good enough about it to start drafting it.
In graduate school I was initimated by the academic writing process, so I knocked on the door of a famous scholar named Alastair Fowler, who is now Regius Professor Emeritus of Rhetoric and English Literature at the University of Edinburgh. He taught at the University of Edinburgh half the year and at the University of Virginia the other half. Lucky us. I don't know what came over me that day in 1990, or why I thought he of all people would help me given his international standing in Renaissance studies, nor do I know why I was so blunt that morning, but when he asked why I had come I blurted out "I don't know how to write a paper for graduate school." He laughed and motioned for me to come in and sit down. "I wish," he said, "that more of your colleagues would admit it." Then he gave me a 40-minute talk on getting your thoughts on paper without putting them in straight lines or any particular order (he preferred using oversized white paper that allowed you to write all over the sheet, be circular, etc.), not setting them in concrete too soon, but allowing your written musings to naturally coalesce into meaning. "Ideas are like sheep," he said, indicating that they want to wander and to a certain extent should, "but then you have to put a pen around them." He showed me his method of circling related ideas and gathering them into intellectual units that would eventually become paragraphs and chapters.
It worked so well that I yammered about it to all of my friends, and a number of them went traipsing to him. Eventually he began offering it as a talk for graduate students, and last year I noticed that he published a book with Oxford called How To Write. Some like to say it's for novices, but I laugh at that notion. Many of the most seasoned writing veterans keep about them the "novice mind," and accept instruction willingly from new sources. I think anyone should read it, no matter how well-published, because Dr. Fowler's insights are unlike any other.
NB: I have no idea if my blurted-out question eighteen years ago actually inspired this book, but I like to flatter myself and think so. At the very least I believe I contributed to it by helping blaze a path for other graduate students to his door.
So how do I start writing? Simple. I take the aspect of the story that interests me the most, and I map it out with the Alastair Fowler Writing Method, hearing his words all the while in my ear "Ideas are like sheep..." I don't pressure myself to make this written bit long or short -- it's just a bit. Some pages. I don't even worry about where it will go in the book. Instead I marshall the research for that tidbit, read it, think about it, map it (mindmaps are also good for this, and I used them often), and then in straightforward prose write it up. Those few pages are just a snippet, but they represent what I can see now. It's like Anne Lamott's concept of the one-inch picture frame from Bird By Bird. She says that her only job is writing down what she can see in that tiny space, nothing more.
So today I'm writing about the day my author went to prison. I don't even know how she got out, but it doesn't matter. I simply know that she went, and I'm sticking to the documented facts of the case (what we have from newspaper accounts and judicial records). I'm writing my one-inch picture frame, using Alastair Fowler's insights, and standing on the shoulders of these two giants.