The Good American Witch by Peggy Bacon. The witch grants wishes, but always with an odd price-- for example, a girl who wants curly blonde hair has to give up her eyebrows. As a result, she gets eyebrows which match her hair. Towards the end of the book, a boy wants to become an artist. He's told the price is that his wish won't be fulfilled until after some large number of days. At the end of the book, he's become an artist, and only then realized that while he's been studying art, the requisite number of days have passed.
The Paladin by C. J. Cherryh-- as I recall, it has quite a lot about martial arts training.
Would the Harry Potter books count as an approximate match? Talent is important, but the characters also spend a lot of time on study and practice.
I haven't read the Potter books for a long while, but from what I recall they're pretty good at avoiding instant-gratification solutions when there's some specific plot coupon that the protagonists need to master. The Patronus charm, the Polyjuice potion, etc. Harry even tries hard and fails to learn an essential skill once, with Occulemency, which is practically unheard of in fiction.
It doesn't seem to generalize very well, though. The protagonists are mediocre students aside from Hermione, and after the first couple of books her studiousness seems to ...
As people who care about rationality and winning, it's pretty important to care about training. Repeated practice is how humans acquire skills, and skills are what we use for winning.
Unfortunately, it's sometimes hard to get System 1 fully on board with the fact that repeated, difficult, sometimes tedious practice is how we become awesome. I find fiction to be one of the most useful ways of communicating things like this to my S1. It would be great to have a repository of fiction that shows characters practicing skills, mastering them, and becoming awesome, to help this really sink in.
However, in fiction the following tropes are a lot more common:
Example of exactly the wrong thing:
The Hunger Games - Katniss is explicitly up against the Pledges who have trained their whole lives for this one thing, but she has … something special that causes her to win. Also archery is her greatest skill, and she's already awesome at it from the beginning of the story and never spends time practicing.
Close-but-not-perfect examples of the right thing:
The Pillars of the Earth - Jack pretty explicitly has to travel around Europe to acquire the skills he needs to become great. Much of the practice is off-screen, but it's at least a pretty significant part of the journey.
The Honor Harrington series: the books depict Honor, as well as the people around her, rising through the ranks of the military and gradually levelling up, with emphasis on dedication to training, and that training is often depicted onscreen – but the skills she's training in herself and her subordinates aren't nearly as relevant as the "tactical genius" that she seems to have been born with.
I'd like to put out a request for fiction that has this quality. I'll also take examples of fiction that fails badly at this quality, to add to the list of examples, or of TVTropes keywords that would be useful to mine. Internet hivemind, help?