People are generally pretty bad at staying organized. A common problem is they keep a todo list, or queue, of things to revisit. But the list gets too big and they can’t revisit all of them. They add new things to the list faster than they finish things and remove them from the list. The basic solution to this is to intend to do less stuff. Recognize how much you can actually get done and don’t plan to do more than that. Some people manage to go through their whole lives with unrealistic expectations about how much they’ll do, even though it never works. Don’t do that.
There are also some reasons people purposefully plan to do too much stuff. If you plan to write a book, you can feel like an author without the work of actually writing a book.
Popper and Rand both wrote essays and later put them into books. So one way of writing a book is to write short pieces on a particular theme and put them into a book on that theme.