Making vocabulary your primary focus is not something that I recommend. And this goes the same as memorising new words, too.
When I was studying for the Japanese Proficiency Test, I worked with a tutor who made me memorise loads of words. Sure, it worked. But it was painful and I hated it. And I ended up forgetting most of it in 2 months… so it’s basically useless. So I don’t recommend memorising words.
Instead, focus on speaking well in conversation in general — on blocks of English. See, if you concentrate on learning these blocks of English or what I call “chunks” (which you can learn more about in my free training here), you’re going to sound more natural when you’re speaking.
But there are exceptions to learning vocabulary. If your goal is to get good at a very specific topic, then yes you should focus on new words. If, for example, you work at a car company. You’re at a meeting that’s being held primarily in English. Of course, you’d want to learn the English words like, “seatbelt” or “brakes” or any other English word you might need in your English meeting. The point is vocabulary learning is definitely better done in specific topics. Memorising words isn’t that useful in terms of general conversation, but it will be a huge help in specific topics.
And instead of memorising and retaining vocabulary, the best way is to learn from context. Find high-quality samples of English and learn what you see (or retrodiction).
There’s a section in the free training I mentioned about the best materials you can use (and what you can avoid) when it comes to chunking and retrodiction.
Hope that helps.
Dr Julian Northbrook