People often either overestimate or underestimate language learning, both ways you'll end up learning little to nothing.
It's therefore important to know how to learn, before you consider to know what to learn and when to learn.
Most people think language learning as either a theoretical thing or a practical thing, and then execute it incorrectly.
Language learning is both a theoretical and a practical thing, as well as a psychological thing, which is what way too many people overlook.
Alongside there are reading, writing, listening, and speaking, the latter is also often forgotten.
The theory side is recommended for the very basics of a language, and should only be used up to begin intermediate level (because they get useless afterwards, since books, learning apps, etc. are always aimed at the absolute beginner, even if the title is "for advanced learners only").
The practical side is recommended for getting used to a language, and should be done from the mid-basic level with no end limitation (in the end, you'll be using a language in real conversation, therefore it should never end).
The psychological side is crucial for the entire learning process, until you feel like the language feels natural to you.
With this part you have to set your ultimate goal, then tear it up into smaller, more achievable mini goals.
For example, "I want to be fluent" is an ultimate goal, but never set it as a mini goal, because:
1. How fluent is "fluent"?
2. When do you expect to become fluent?
3. What do you want to do with your fluency?
And so on.
