Good technical writing needs to be concise and unambiguous. Same with rulebooks. Showing someone how to do something through pictures, icons, arrows, etc is always better than text. Same with rulebooks. In fact, I would consider rulebooks a form of technical writing. I’ve also learned that there is a sort of fuzzy wall, a wall whose borders are not quite clear and that doesn’t stand tall enough that you can’t easily step from one side to the other, but the delineation exists nonetheless between art and graphics design. Graphics design and the actual text saying what to do, when and why are the meat and potatoes of the rulebook. On the graphics design side of that fence, showing pictures, arrows, etc is always better than just plain text in telling people what do to. I’ve also learned recently that proofreading/editing has similar demarcations I never knew existed. I always thought that crossing Ts, dotting Is (eyes) and correcting minor spelling and grammar errors were just part of what went into proofreading. In fact, in my previously uneducated opinion that was the least important part: wouldn’t it make sense to completely abolish a paragraph that didn’t belong before you bothered telling me I’ve misspelled football in an article about baseball? According to this article, the type of editing I care most about during the composition process is “substantive” or “developmental” editing. This might be similar to the “Sanity Test” offered by the gamecrafter. The page does describe their process as the more holistic idea I had of proofreading before I did all my research and I had thought about using them, but your game must be on their site for sale before. However, their criterion is transparent enough. There are plenty of other sources that offer good guides for writing a rulebook.
I have to wonder about this one, though. It’s free and operates on a donations basis.