Don't focus on the 'intended material' (unless you have some responsibility for it), follow the "lines of inquiry". Trust your instinct: You will learn better the things you have a passion to learn, will enjoy, and are ready for - that are not a step too far; your instinct guides you toward where you are ready to build next.

And I think people learn better by inductive, exploratory learning than by some predefined path (and I've read things that support my theory, but I can't say I've looked for or seen any great evidence). Trusting my instinct has made all the difference for me.

I do have to prioritize, of course - there isn't time to follow every path. I'd like to learn just about anything in the universe. But at the same time, when I choose something, I follow it (almost) as if there is no time limit.