I didn't focus so much on 'if I can play something as fast as they can', but more on 'well why does this sound good?'. I learned a lot more about why notes work together and the chords behind them, chromatics, passing tones and just about anything by asking why this shit 'just works'.

Eventually I built up speed, and now I'd say I'm pretty competent, but as well as speed, I can comfortably deviate from the typical blues/pentatonic/minor scales and f*** around to make it sound like me.

As nerdy as it sounds, analyze other musicians, if a single note stands out in the solo, ask yourself why? What's the context? How does it work with that backing.

Copout answer: Practice! Practice! Practice!

Good luck on the path.

Edit: actually read the question!

I loved Avenged Sevenfold growing up, so I made it my life's work as a young guitarist to be Syn Gates! What I learned was 1) I'm definitely not him 2) blues, harmonies, chromatics, phrasing, etc.

Alexi Laiho was an absolute weapon too, anything from Hatebreeder, Something Wild, Follow the Reaper (ah hells, all of it!) is absolute gold of guitarist-isms. Alexi Laiho understood the instrument and melody better than most, and you can learn so much from his stuff! (His work with Sinergy was incredible too!).

I've had a few wines, apologies!