Hey, I noticed in the OP you asked about what people learnt that gave a them a major proficiency boost.
Not sure what level you are at (if this is old news then maybe someone else will find it hand) , but for me , one major “level-up” was when I learnt the notes of the minor pentatonic scale (in say, A minor) which led me to jamming along to blues stuff, or TV commercials, or my own looped chord progressions, or these days just backing tracks on youtube. (My Fender GT40 isn’t very highly regarded but 1 thing I love is that I can use it as a bluetooth speaker for my phone while simultaneously rocking out).
I kind of knew the scale already, but I didn’t understand it. Once I realised it’s more about the intervals between the notes, I realised the A minor pentatonic scale was the same as the B minor scale, only it starts on an A instead of a B, and so on.
**Oh yeah, the scale itself is handy for learning where the notes are, but the point is to use the individual notes, often out of orders, to come up with licks etc that sound cool.
The other important bit I’d missed when trying to play lead over some chords (say 12 bar blues), was which notes in the scale were the root notes (In A minor, the root note is A). So basically I’d see all these frets that should sound cool but it just wasn’t right, but once I started finishing/resolving on a root note, I started sounding like an actual musician.
Not sure if that makes any sense, but it meant that I could just sit and noodle away for hours, come up with solos, or just generally sound like I knew what I was doing without having to remember a song to recite.
Anyway, the way I learnt it was by looking at the fretboard map (hopefully shown below) or you can see it here: https://guitarsecrets.com/a_minor_pentatonic_scale.htm
Basically I learnt the yellow box and then added the notes up to the 12th fret, which gives you 2.5 octaves to play with, and you can see all of the root notes that are good for resolving or getting you back to base.
This will generally sound good with any 12 bar blues in A, and really opened up a whole new world of scales and playing along to backing tracks. And youtube is your friend when it comes to backing tracks, you’ll feel like a god jamming to some of their “epic rock journeys” etc, and many of them even show you the chord progressions and fretboard maps to help you along the way.
I wanna get home now and rock out, \m/