Domains
As we've previously discussed, there's always an uneven distribution of word usage. The most common 20% of words are used 80% of the time.
As you start hitting the intermediate stages, you'll notice your comprehension grows more slowly even if the number of new words you learn stays the same. This is a good indicator that you've hit a more advanced level and are ready for a change in strategy.
New Strategy

Even though the uneven distribution of language becomes frustrating at this level, we can use it to our advantage.
As a general rule, your "core" language is everywhere you go. This is why that first 80% is always so easy to learn. You couldn't avoid this vocabulary if you tried. For specific vocabulary, this isn't true.
If you're watching a fantasy show like Lord of the Rings, 80% of the vocabulary at this point should be a walk in the park. The remaining 20% is highly specific, and this is what we'll use to our advantage. Luckily for us, there's still a pattern to this remaining 20%. It is always highly specific and domain relevant. In Lord of the Rings this vocabulary might include elves, dragons and dwarves.
Introducing Your First Domain
This is the fantasy domain. A domain is a subset of a language, including the vocabulary particular to it. As we understand by now, exposure is the key to language learning. If you need to learn specialized vocabulary, you need to be exposed to it a lot. We can artificially increase this exposure by honing in on a single domain.
Your first domain may not be fantasy. It may be romance, slice-of-life, or even music. Whatever it is, you know enough of the language by now to follow your interests. We suggest you do this for your first domain. You want to now spend the bulk of your time in this domain. This increased exposure will make learning those rarer words much easier.
By the time you've mastered your first domain you will be pretty fluent in your target language. From here on out, what you do with the language is pretty much up to you.