Lots of people can write beautiful prose, it’s structure that’s tricky. Novelists can afford to just start writing and see where it takes them, writers of non-fiction need to have a plan. Draw up a list of “landing places”, points in your narrative where your reader can have a bit of a sit down and admire the view so far. Your job as narrator is to lead them from one landing place to the next, neither chivvying them along nor allowing them to lag behind. Make sure, though, that you don’t come over like a drill sergeant. The trick of good narrative non-fiction is to allow the reader to feel that they have worked it all out for themselves.
Some good advice by Kathryn Hughes, ‘director of UEA’s MA programme in biography and creative non-fiction’, in the Guardian's 'So you want to be a writer …’