Writing a series, I've read and discovered first hand, is a bit tricky. It's not just the effort required to continue the story's characters and their adventures, but to ensure additional books make sense for the reader who did not have the pleasure of devouring your debut book. Many authors, myself included, wrote the debut several months, maybe even a year or two prior to the next in a series, and it's a challenge to keep track of all of the details that were sweated over while making that first masterpiece. (What was that minor character's name? Was it Tyson or Tyler, and did he have blue or brown eyes?)
To keep my memory banks, faulty as they're becoming, from experiencing a full melt down, I have resorted to a tried and true method. The good ol' spiral ring notebook. Never crashes. doesn't break if I drop it. Page never freezes up - I can turn 'em as fast as I want. I can make as many files/categores as I need ( sticky notes are a wonderful invention), and I can check up on details in the notebook at the same time that I am typing my manuscript - no fancy split screen needed. Best of all, just handling the thing takes me back to the times of junior high Creative Writing classes - where a binder full of spiral ring notebooks bulged with my imagination caught on paper - and there's still a subconscious thrill of opening the notebook's cover, a sense of one about to be taken away into a very pleasant place. Sadly, a computer file just doesn't do that for me.