Learning a language is a delicate balance between extensive and intensive application.
When you are doing things in an extensive way, you process a lot of text lightly, skimming over it, skipping the stuff you don't know, being satisfied with grasping the overall story.
The intensive approach is more intense. You concentrate hard on the language's features and try to remember them.
That's study, in other words. That's work. It's forcing your short-term memory to do a job it's not designed to do. It's like heaping on the fertilizer in order to achieve artificial growth. And then you return the next day to see that your plants have collapsed. Or, if they still stand, see that they have mutated.
Nevertheless, you need a balance of both approaches. The balance point should favor the extensive side, but it's human nature to try to control the learning process by heaping on the intensity.
Don't think of 'learning', 'studying', 'memorizing', or 'drilling'. Instead, think of noticing various features of the languages as you gloss over it.
Yesterday I noticed that with Spanish some words start with a double 'L' and that sentences may not start with a capital if it is a 'small' word such as 'y'. I noticed how n's with a ~ above them are pronounced.
I must have noticed a 100 or more features. Each time that they do, they seep into my long-term memory a little deeper. I internalize them naturally. And all those features support each other in an organic, holistic, intertwined . . . what's the word I'm looking for?