I suggest you pick a direction and keep pushing. There's a particular set of projects I sometimes look at, and I find them overwhelming. I think, "This guy is way ahead of me", or "This guy is way smarter than I am". But here's the thing—they are projects I did myself:

* This guy is way ahead of me: http://railstutorial.org/book

* This guy is way smarter than I am: http://thesis.library.caltech.edu/1940/

I only feel overwhelmed because, in a single moment, I'm looking at the cumulative effect of months or years of effort.

Pick a direction, and just keep pushing.