Do you have a favorite "Accessing Data in Nested Structures for Complete Idiots" tutorial that you could point me to?
Not as such, no. I wrote up a post some time back on a related question, but it's mostly about syntax, not the semantics. At one level, of course, it's simple; unless you're dealing with a "top level", you've always got a reference until you dereference it (implicitly or explicitly). But presumably your troubles at somewhat beyond that?
However, ikegami's post is cogent. Think locally; you never deal with a giant data structure. You deal with at most a slice of a data structure, and usually a piece of data. If you can answer the questions "what piece of data do I want" and "what do I want to do with it", it's usually a lot easier to figure out how to go about it.