Having found the Drupal API documentation less than accessible/usable, I am finding it easier to reverse-engineer other modules and the core code to find what I need to know. To keep my notes together, I am using the blog module of this site to created a Development Journal. This, if anywhere, is where I will also explain the logic behind what I am actually doing - it's probably as close as I'll ever get to documenting my code.
If anyone sees that I have drawn any incorrect conclusions from my reverse-engineering, please feel free to correct me by commenting on the appropriate blog post.
Note that items from the Development Journal will also appear on the front page, but non-Development Journal items will not appear in the blog.