Learn a little at a time. Don't compare your knowledge to other's or to the total amount possible, just to what you knew before. Keep it up and you'll slowly get better and better over time.

I also find it useful to keep a short file of features I want to learn and features (1 or 2) I'm currently learning (trying to use as much as possible even if it slows me down a bit so that they'll stick in my mind).

That's one of the reasons I wrote this. One thing you could do is write scripts in it. Or smaller programs.

One thing I'd really like to do is to make a massive index of emacs-lisp code on github. That would be a fantastic resource.

You mean like https://github.com/emacsmirror? :)

No, that's just a list of stuff (there are other really good pointers to elisp on github too) - I want an index of all the functions and variables used in the code there, hopefully with a usage index (where is find-file used?). It would be big data but totally awesome.