[Gordon Currie]

I was fortunate to have some early experiences playing in bands starting in 7th grade AND playing with good drummers who drilled TIME into me, so playing with others and timing weren't big Achilles heels.

My big issues I had to work to overcome:

-Education. My first lessons at 9 were terrible. I then opted out of lessons of any kind for over ten years.
I had a common (but inaccurate) belief that the best players figured EVERYTHING out for themselves.

Turns out that certain things are just orders of magnitude easier to grasp when taught by someone else.

-Slow practice. When I was first learning a lick or a piece I would play it slow (I had no other choice). But right away I would crank up the tempo, regardless of how sloppy it was.
It took too long for me to realize that muscle memory could be your enemy. Practice something too fast, and the sloppiness/mistakes will get quickly embedded into memory.

These days, if I hear a mistake once, it's just a mistake. If I hear it twice, it is a red flag that I am about to commit it to muscle memory. Time to slow down right NOW.

-Proper setup. I started playing in the last half of the Sixties, and no one I knew ever talked about getting their guitar setup. I don't remember hearing about compensated saddles until late Seventies.

Because of this, I didn't experience a good setup on my guitars until 20 years in. I regret the years of expending much more effort than I needed just to get a decent sound.