I use physical folders to bring together the few non-digital things I create as I'm working on a pattern. It holds my swatches, my first draft of the pattern with my notes, and any sketches I draw by hand. All of the folders go into one storage file, so that I don't lose them. The patterns, samples, and swatches for my book are all in their own storage file box. (I borrowed this idea from Hunter Hammersen, and I love it.)
In theory, it could ALL be digital, but I still end up with some physical stuff because I find proofreading (and making notes while knitting) on paper easier.
As I near the launch date for a pattern, I like to use the outside of the folder to outline finishing-touch goals for myself, with deadlines. I have a terrible memory and if I don't write things down, I literally lose sleep because I'm so worried that I forgot something.
The pattern is back from the tech editor (the lovely Stephannie Tallent), so all I have to do now is add some finishing touches to get ready for the pattern's pre-release next week.