Some time ago, I came across the Wikipedia article of Niels Henrik Abel, and something there burnt its way into my mind.
Abel changed the face of mathematics, despite dying at 27. And here comes the thing – I give the mic to Wikipedia now:

When asked how he developed his mathematical abilities so rapidly, he replied “by studying the masters, not their pupils.”

By studying the masters, not their pupils.
The proposition is a bit like trying to climb a wall instead of a stair. Already I found straining to follow the gist of the textbooks of the subject I was interested – how could I deal with the masters?
Yet, maybe you don’t have to be Abel to do what Abel does.
Another thing that resonated deeply with me was how Newton studied a book by a French mathematician (I don’t remember which one): he started reading the book – when he found it too hard, he started over. That’s what he did until he understood the whole thing. So, he didn’t go and read something more basic, or tried to found someone who could explain it. He just stayed with the source until he groked it.
Again, Newton was a genius. But may be this kind of thing is what we need to truly learn, to truly get a shot at doing something of beauty and usefulness.
I’ve been reading the masters more and more. Usually it’s like reading a foreign language. You don’t understand almost anything and you feel like a baby.
But if you don’t mind too much feeling like a baby, and if you can create some space in your life where you aren’t forced to be an adult, then give the masters a try.
Below I put some links to works by masters of Computer Science – all the works below are available to download for free.
Shannon, 1948 – A Mathematical Theory of Communication
Shannon, 1949 – Communication Theory of Secrecy Systems
Turing, 1936 – On Computable Numbers, with an Application to the Entscheidungsproblem
McCarthy, 1960 – Recursive Functions of Symbolic Expressions and their Computation by Machine (Part I)
MIT, 1962 – Lisp 1.5 Programmer’s Manual
Ritchie, 1993 – The Development of the C Language
Thompson, 1984 – Reflections on Trusting Trust
Cerf et Dalal et Sunshine, 1974 – Specification of the Internet Transmission Control Program
Wu, 1997 – The Secure Remote Password Protocol
Strachey, 1967 – Fundamental Concepts in Programming Languages
Knuth, 1983 – Literate Programming