I have 1 book of general ideas (because I have to keep them somewhere) but I work individual journals for each game I am developing (Top Deck now fills 3 books). I recommend individual design journals because it focuses the mind (you know what game you are working on because you are in that journal), it centralizes information (all notes for Ender Dungeon’s Last Crawl are in one place), and you feel like a bad son-of-a-gun carrying a notebook filled with a year’s worth of blood, sweat, and tears. *If you struggle with information to write you should probably review this post.
I use actual paper notebooks. Writing by hand is usually faster, definitely more accurate, and is a bit more free flowing than typing on my phone. My notebooks are quiet, low light, and can go ANYWHERE with me. When its 0830 and I’m supposed to be in bed so I can wake up for work, I’m not going to whip out my laptop and work on a Google doc. That idea is going to trouble me all day if I don’t record it, though. So, out comes my notebook, I throw down some furious scribbles, and my wife gets to keep sleeping.
Next, I write as if I am talking to a friend about my game. Ever have those days at work or school where you HAVE to find some help for a confounding problem or assignment? When you chat with the help, you do most of the talking and solve your own problem? Yeah, that’ll happen in your journal because sometimes you just need to talk through an idea. As you write, fill in all that you are feeling and thinking – just like you would when updating that friend. This casual conversation with yourself makes reviewing information a lot easier, too. You can see clearly on those pages what you were experiencing when you came to those conclusions.
Write down everything pertaining to development. In the beginning, write about what you hope the game will look like, how it will feel, how it will look, etc. Dream big! As development progresses, include brainstorms, criticisms, play test results, etc. Now, you don’t have to include specific statistical data, but you should include summaries and lessons learned. That way, when you go in to fix and fine-tune your game, you need only flip back a few pages to see why certain changes were made last time, why you thought that clunky mechanic should be added, and why that thing you love was removed. *If you are struggling with adding information about what works, what doesn’t, and what can be generally better you should probably review this post.
Finally, my favorite part about having one notebook per game with every thought, lesson, and idea written down, is what happens when I open it to the front. There, I see where this beast started, understand just how far it has come, and refresh the values and principles which gave birth to this dream.