Whenever I am able, I write up my stories for DnD in a book. The Rappan Athuk adventure I ran awhile back was written down in a “Music” book that I bought when our Waldenbooks was going out of business. My method is to write everything down that I plan to play through, and then start adding flavor text, color, and sometimes stickers. For example, the bomb stickers in the Rappan Athuk book were to call out traps to catch my eye. The treasure stickers were to remind me of goodies that the playing characters might find. I bought the stickers at JoAnn Fabrics a few years back for a $1.00 a book. I bought something like 20 books.
Here’s what a usual story looks like when I write it all down. It ends up looking like a scrapbook almost. The first time one of my players caught a glimpse of this book, his reaction was: “WHAT is THAT?!”