I've just made the following article: Manual of Style.
It is not done yet, but we need your help. We'd love it if everyone would read through it and comment on the talk page of the article.
Also feel free to add to it, because, as you can see, it is clearly not done yet.
As an extra bonus, there will be 'a unique user-page badge' (not an achievement) for contributing to this project. Who doesn't want that, right?
Thanks in advance!