I've been trying to read through the RoR API to try to learn things that the tutorial missed, and I haven't been able to follow it at all. The only time I've read documentation was when I needed to look up a Python module, and that was easy to understand, but I can't understand the docs for Rails. How do I read through API documentation?
For a start, you don't learn a language (or how to use a library) from a reference pages. That what the tutorials are for starters.
For more advanced topics, if tutorials are missing, find good blogs, or a good book.
Having said that, reference pages are there to see details of a function (for example parameters and their types).
The way to do it, if you insist on pulling info from the API w/o using as what it really is - a reference manual - would be to come up with a small program for each item in the reference/API docs and actually create code for it. In other words, to learn code, you must code, end of the day, that's the only real solution.