For example when I wanted to learn how to read music, I looked up all the information I could on how to read music, but I wasn't satisfied with it so I came up with my own system for learning to read music without using note names, then later I found that someone had done something similar because after I had developed the system I kind of had different terminology to search.
But when I wanted to learn Chinese, I downloaded a few apps and found a good one I liked, and I use it every day. I also found a good Chinese podcast that I listen to while walking, running or driving. I didn't have to come up with a better system, the apps are good.
When I wanted to learn how to swim better, I looked on YouTube for good swimming techniques and ultimately found Total Immersion, so I practised that by following the video instructions and swimming all the time. But then I found I couldn't speed up and there are no coaches for TI swimming, so I just took some advice from faster swimmers.
When I wanted to learn how to touch type as a teenager I just used a touch typing application that I found in a big box of old floppy disks next to the computer.
When I wanted to learn about MMT I read books, watched hours and hours of YouTube videos, communicated with academics, created my own content about it explaining it to others and discussed it online.
When I wanted to learn about physics I watched all the Leonard Susskind Stanford lectures on physics.
When I wanted to learn how to eat more healthily I listened to some podcasts while walking, I did take a couple of notes on some things, but then I immediately put those notes into practise by finding a couple of simple recipes I could work into my daily routine. I'll never forget those things, because I practised them immediately.
Another example of this type of learning was when I wanted to improve my chess: I didn't do lots of study, I just learned that using openings and defenses was more useful because a good strategy sets the board up better than trying to fight tactically all the time. So I learned one opening (Queen's Gambit) and one defense (Hippo) very thoroughly, and then practised chess a lot by playing simultaneous games in an app. I minimised the amount of information I would need to remember, then did lots of practise. My chess playing improved a lot!
I don't usually bother taking notes on stuff in any sort of structured and searchable way, but sometimes I write about what I've learned, and I will quite often share the most interesting parts with people in conversation, sometimes I can't quite remember something, so I'll look it up again.
If something's really interesting and I consume a lot of content about it, then usually the same concepts pop up time and time again, so I don't really have to bother note-taking, it just sticks in there because I hear it over and over again. A good example of that is Mixergy: when I first started listening, I worried about how I would remember all this amazing information, but then Andrew as nice enough to have a chat with me via Skype (in 2011!) and he told me "don't worry, all the best info comes up over and over again, it'll be in your brain when you need it" and he was absolutely correct.
Usually it's enough to know the thing I forgot exists, because I can just look it up again online more easily than I could search it in some notes that I'd taken.