Know Yourself: there are many learning styles, most people lean towards one (e.g. visual, verbal, learning by doing or physical).
https://www.learning-styles-online.com/overview/
Motivation and inspiration play a huge role. So, Why are you learning something? If there is a profound motivation to learn something, with deep meaning, then learning becomes exponentially easier. Think of the neurochemistry involved when comparing an activity which intrinsically always produces joy, vs. trudging through an activity which only causes suffering.
https://www.amazon.com/dp/B004P1JDJO/ref=dp-kindle-redirect?...
So then a hack is convincing yourself of profound meaning within the thing you're attempting to learn.
https://www.amazon.com/dp/B000W94FE6/ref=dp-kindle-redirect?...
Study Flow. Someone posted the idea that we want to avoid autopilot. I agree one must really focus to be mindful of what is contributing or conflicting with their learning. But I somewhat disagree, as the experience of Flow, when the challenge is great, is actually ideal, and in my experience is akin to a form of conscious autopilot. Once a skill is mastered, and flow is harnessed while competing at a high level, then one can recognize optimal experience as optimal performance, and thus the goal of learning and mastering a skill. I know English, and I don't have to think about each word to generate a sentence. I can think about the central concept and let the words come on their own. As a software developer I think way less about syntax and language nuances, and more about the problem I'm trying to solve, then the solution arrives on its own. Yes raise the bar, and yes pay attention to difficulties you have, overcome the gaps in knowledge and skill, then experience flow, enjoy it, iterate on that. I think a key is recognizing how to enjoy it, so you keep coming back to learn more.
And then speaking of concepts, think of Jungian Archetypes or Mythological Abstractions. Jung believed the realm of the unconscious was just as real as the computer you're interacting with. Out of this realm arises abstract concepts which apply to all of human psychology, across humanity (cue OO programming, and abstraction layers, for the programmers in the room). So then, discrete concepts can fit into their parent abstraction. Arts like Jiu Jitsu, reflections on human nature, leadership in business and studies of military strategy, can overlap with one another (the Jocko Podcast is a great illustration of this). So then once you begin to master a skill, you can take abstract concepts and apply them to something new, only expanding on what you already know about yourself, rather than what you might consider to be completely foreign.
Of course, all the suggestions on this page are certainly helpful. When it comes to learning skills, I have a tendency to look a bit deeper in order to learn quickly. I believe there is a mindset where 100 hours in a new skill, leveraging 10000 hours in a previous skill, will be far superior to the 500 or 1000 hours of deliberate learning when the focus of learning is too narrow and the overlap isn't noticed.
It's like sports or strength training. Steve Nash grew up playing soccer first and didn't start playing basketball until middle school. Michel Jordan wasn't great at baseball, but he still played professionally. Anyone remember Bo Jackson? "Bo Knows" baseball and football.
Just thoughts, hopefully stimulating and helpful.