Hands-on experience is the best resource. Watch YouTube, fine someone with the same interest, ask on forums such as this one here, find old parts you are willing to lose/break.
started learning when I was a kid, it was just fiddling around with PC parts and learning what is what and how they interconnects, later learned from books and finally youtube... that makes me feel old.
Started coding on a Commodore 64. Then got into hacking, got caught and ordered to do community service but director of firm I hacked twice ask judge to make me work for them during school summer holidays.
While there I did various roles including sorting their security. They gave me cart blanch on hardware so I built myself a shit hot PC for my use.
Then my IT manager wanted one so built him one also.
By the time I finished there I went into networking and server security for a couple years.
Got bored of that so moved on. By this time vodoo cards were the business.
So another tug got built and started serious gaming.
Did a dead end job and started a family but always kept a rig in house and built many others for clients on the side.
Trained in mean time as an engineer then did a few jobs in that field which have me experience and know how to come up with ways of doing the unusual and more importantly his to fix things.
So yeah as guys said. Hands on and years of experience but more importantly the mentality to try summin even though never done it before and learn from mistakes and try again but harder and better.
Old saying: you won't know till you try.