You can sum up (what I think) is the most effective way to acquire a language in one sentence.
Consume content that interests you in your target language.
That’s it. No secrets. It’s hard to sit down for 1 hour and study grammar (unless you like grammar). It’s not hard to sit down and read/watch/listen about a topic you enjoy (in your target language, of course).
Speaking is important to but it shouldn’t be the primary goal.
Input drives output. We can all consume more in our native language than we can speak. You can read and understand a complicated piece of literature but it’s highly unlikely you could replicate it in natural so each. The same is true in any second language.
Focus on input and the output follows, without much effort.
If you’re interested in learning any language you should check Steve Kaufmann. He has ton of great insights and has greatly helped shaped my opinion on above.