I have to disagree with at least one point in Ben Scofield's talk.
If you are doing deliberate practice and you are failing most of the time,
then you are either not trying hard enough or you are setting your
goals too high. Deliberate practice requires setting your goals
right at the very edge of your capabilities. If you are doing your
very best, you should be succeeding at least 50% of the time.
If your practice is soul crushing then it will be very hard
to sustain the necessary effort for 10,000 hours (or even much
less time).