Just how carefully did J.K. Rowling plot out her Harry Potter novels? Incredibly carefully, it turns out. Behold a chapter-by-chapter spreadsheet of Order of the Phoenix, covering the prophecy, Ginny and Cho, Snape, and a bunch of other stuff.
This image has been floating around on the internet for a few years, but I hadn't seen it before and it's really astounding. The amount of attention to detail and making sure that the various elements move forward at the right pace so that they all land where they're supposed to... it's the sort of thing you expect from television shows with several writers. Also note that she keeps careful track of the dates when things are happening, something that is really important and neglected in fiction. (The passage of time, I mean.)