So here is one of the problems I am running into.
I cite from Molly's book.
“Imagine little me in the practice room: I’d play the measure my teacher said needed work and maybe it was perfect on the first try. Hooray! Maybe the second try was also great. But on my third try, I was distracted by something, so that time wasn’t very good. Okay, that one doesn’t count. Fourth time: also not great. Doesn’t count. Fifth time: good! Now I have three correct, two incorrect. I would continue like that until I had 10 correct ones.
You can imagine, though, that by the time I did 10 correct repetitions, I probably also did 10 (or more!) incorrect repetitions that didn’t count. In that case, I had accomplished literally and precisely nothing (except wasting my time) because I had reinforced the correct pathway 10 times, but also the incorrect pathway 10 times. I still had two completely equal pathways, and therefore only a 50% chance of it going well. [...]
We need to ensure that the correct pathway gets reinforced many more times than the incorrect pathway. [...] To accomplish this, it’s important to have a consequence for an incorrect repetition. To make this happen, add the words “in a row” to the number of correct repetitions you plan to do: 10 times correctly in a row. This means if you get it wrong on the third repetition, you have to start over again at zero. When faced with the consequence of having to start all over again, you will focus much more, and you will focus on exactly what you need to do to get it right.”
The problem for me is, even when I think the magical thought "ten times in a row" this only works when I practise very small passages, a couple of notes basically, or just one hand. As soon as the passages that I practise get a bit larger, almost inevitably I fail on one of those ten times, not uncommonly on the 7th or 8th time. Even when I divide those ten times in a row into twice five times in a row, it happens way too often that I don't make it to 10 (or 2x5) times in a row.
This is a great source of frustration, and instead of feeling that I progress, I can end a practice session with six new passages written in my notebook that I need to play correctly 2x5 times in a row.
Those of you who work with Molly methods, do you have any advice to me?
PS I wrote my question in this thread, because it is about how to apply what she says, and not a discussion of the validity of what she says.