It can be a small skill.
The last thing I learned to do was whistle. Never could whistle my whole life, and tutorials and friends never could help me.
So, for the last month or two, I just sort of made the blow shape then spam-tried different "tongue configurations" so to speak -- whenever I had free time. Monkey-at-a-typewriter type shit. It was more an absentminded thing than a practice investment.
Probably looked dumb as hell making blow noises. Felt dumb too ("what? you can't whistle? just watch"), but I kept at it like a really really low-investment... dare I attract self-help gurus... habit.
Eventually I made a pitch, then I could shift the pitch up a little, then five pitches, then Liebestraum, then the range of a tenth or so. Skadoosh. Still doing it now lol.
(Make of this what you will: If I went the musician route my brain told me to, then I would've gotten bored after 1 minute of major scales. When I was stuck at only having five pitches, I had way more longevity whistle-blowing cartoonish Tom-and-Jerry-running-around chromaticisms than failing the "fa" in "do re mi fa".)
So, Lemmings: What was the last skill you learned? And further, what was the context/way in which you learned it?
Absolutely the hardest part was the shrinking. Most of the damage, I had access to both sides of the panel. Which means you can use a hammer and a block thing called a dolly. But you have to hold the dolly on one side and hammer on the other. Which is awkward as hell. It's slow work, or was for me; I suppose a pro can go faster. And you have to be careful because if you overdo it, you can end up hardening the metal and end up with cracks.
All the videos and tutorials say to practice on some scrap sheet metal, but I didn't have any, so it was trial by fire.
This was back in the summer, but my left shoulder is still being pissy about the positions I was in to reach the dolly to the middle of the roof and still see what I was hitting with the hammer.
Tbh though, it was much simpler than I thought. There's plenty of good tutorials out there,and the concepts aren't complicated at all, it's the skill that's fiddly and detailed.