I think the thing that made it all click for me was learning how Pratt parsers work, easy to get something up and running in a jiffy while just playing around -- especially if you play around in python. Tons of blog posts on the subject these days.

My current parser fetish is Earley parsers but they're a bit more complicated to get from (possibly multiple) parse trees to an AST you can do something with, still trying to grok how that all works. Probably doesn't help I've been playing with a C++ grammar in my experiments.