I sometimes tell people this idea as a the good news and bad news of learning.
The good news is that you don't need to "try" to learn. Just do something, pretty much anything, for a while and the learning/remembering/synthesising happens automatically. The bad news is that there's no shortcut, it will take time no matter what you actually do.
Even quicker. Bad news, it takes time. Good news, it only takes time.
It is so effective that you don’t need to read the article the title says it all.
Most people fail at keeping this rule because their mind perceives it to be too simple to keep and falls prey to overconfidence.