I'm reading a fascinating book entitled "The Practice of Practice" by Jonathan Harnum. It's published by Sol Ut Press. There's a lot of material to digest a chapter or two at a time. Essentially, Mr. Harnum consolidates current schools of thought on practicing from musicians to psychologists to neuro-scientists. There's a lot of material on how we process practice and doom ourselves to falling short in performance instead of taking the time to reinforce good practice behavior while eliminating self-defeating techniques. And yes, you guessed it, much involves slowing down. As my teachers always said, "If you can't play it slow, you'll never play it fast." But there is science behind it, not just some musings by an experienced teacher.
I'm a big believer in the power of the metronome. It's what my private students know as "my personal torture device." It took me years to understand it's benefit and now I strive to incorporate it as the most important training tool for young students. They've not developed an internal meter and it is frustrating to them, and me, to hear leaps of tempo within a piece. The music and fingerings that flow easily race away, while the difficult drags. I'm reminded of that old joke... "How do you make a guitar player play quietly? Give him music to read."
In fairness to guitar players, there's a greater truth in the statement. We're proud of what we can play, and fear in what we cannot. The problem arises when we don't fix what we cannot play. This book offers some great advice on how to tackle that. Not so much from a technique perspective, but from a mental perspective. We are our own worst enemies. Failure is to be embraced. Slowness is to be embraced. Determination is to be embraced. And sadly, we tend to ignore all of the above and fall forward into a half-baked approximation of what it should be.
There's a lot to learn here. I'd highly suggest this. Read it in bits. Digest it, and read a chapter again. There's also online content that is linked, via a smart phone scan, or typing the links, to reinforce the concepts.
It's worth every penny and long overdue. Check out the website, too. https://thepracticeofpractice.com/