Some things I learned about Rails and writing while working on this book:
The great benefit of working on a project like this book is that it enabled me to compress about two years worth of research into Ruby and Rails tools into six months. In my case, this was a great opportunity to really dig into some tools to find that I've only been using a fraction of their power and also really get a sense of how elegant and flexible the tools are.
Ever since I learned how to type back on an actual typewriter in the mid 80s, I've always followed the old-time typographical convention of two spaces following a period. Which was burned into my fingers despite multiple people telling me that was a silly and counterproductive thing to do in the brave new world of proportional fonts. In fact, on the wx book, I actually did a global search and replace for a period followed by two spaces to get the manuscript to correspond with the publisher's expected conventions. Somehow, I managed to break that habit while writing this book.
The hardest stylistic thing for me to get around was avoiding using "we" and "us". In other books and articles, I tend to introduce examples by saying things like "Now we should type the following" or "Let's see how that's implemented". Wiley/Wrox house style, though is to avoid "we" and write the examples as "Now you should type the following" or "I'll show you how that's implemented". Even more preferred is avoiding the pronoun altogether with "Here's how that's implemented" or "type the following". I'm not saying one way is better or worse -- I find the "we" style to be conversational, the Wiley editors clearly disagree. It did take some getting used to, though.