Nathanael Garrett Novosel
Just get started. So you'll miss a few episodes of television that you'd have forgotten within a few years, anyway. I found it easiest to have an overall point/theme/idea, an end-to-end narrative told by a book outline of just chapter names and a few-sentence descriptions, and then a chapter structure with what needs to be covered within each to take the reader to where you want him or her to be by the end of it. The rest is just filling in the blanks, which is much, much easier to do than having whatever you've written plus a big blank "rest of the book" to complete from there.