Vocabulary is generally the more underrated of the two core components. A huge portion of speaking a language is really just knowing enough words.
Start off by learning the 1,000 most common words as fast as possible. Stretch for 2,000 if you can. That lets you understand a lot of basic language.
Most of your word acquisition will be through ﬂashcards, with much introduced to you through your beginner course and still more introduced to you through your input.
Later, many learners move away from ﬂashcards into large amounts of reading, while others continue to use ﬂashcards heavily.
Key tip: Learn the most common words ﬁrst
Words in natural language follow something called Zipf’s Law, which states that the most common word will occur twice as often as the next most common word, which will occur twice as often as the next most common, and so on.
This means languages are heavily dominated by the most common words. Once you have learned 2,000-3,000 words, you have covered almost all the words you will hear in daily conversation.
With only a few hundred words, you will have access to almost all the filler words, which make up most of spoken language.
This isn’t a free shortcut however, because much of the meaning is contained in the less common words. What it will do is put you in a good position to learn these words naturally and better derive meaning from context.