You must have me confused with someone else. I don't really consider myself an espresso 'next level' kinda guy, you could probably teach someone just as much as I could... if you wanted to. I don't think there's a magical formula to pulling good shots, things that helped me improve my ability to me sort out the espresso wheat from the chaff are:
1) Tasting espresso in a boatload of retail locations where they imprinted their styles, techniques and interpretation of what espresso 'should be' into the cup.
2) Remaining aware of what the forward thinkers are pondering in regards to espresso advancement.
3) Keeping an open mind in regards to my own technique and results.
4) Being a mad scientist with a lot of SO shots and then playing even more with blending.
5) Having the chance to work with some talented characters.
6) Other things I'm too lazy to think about and type out.
I believe the key to helping advance someone's espresso abilities is through careful explanation/guidance down the path without being overly specific and stating absolutes. Everyone develops their own path, I'm not trying to force them down mine and that's why I prefer generalities for a lot of espresso discussion. Generalities allow for personal exploration, some of my 'coolest espresso theories' have produced some of my worst shots but every once in a while I get a step change in improvement. My espresso isn't earth shattering great, it's still got improvement potential, but every year it tends to get better - or at least better understood. I suspect you've observed the same with your own espresso.