When trying to increase fluency, it is often best to work from texts which have few rare or difficult words. Often these less formal texts contain more idiomatic expressions. With such texts you can concentrate on the phrases and pay attention to how the prepositions, articles and tenses are used.
The ideal content for this is natural conversation. People use more common words and phrases and fewer difficult words, in conversations. In my experience, conversations and interviews are interesting only if they are genuine and not scripted for learners. Remember interest is key. Look for conversations and interviews, with sound and transcript as ideal content for intermediate and even advanced learning.
On the other hand to increase your knowledge of more difficult words, especial y words needed for academic and professional purposes, or for tests like TOEFL, TOEIC or IELTS, there is nothing better than doing a lot of reading in your areas of interest. If the subjects are familiar or of interest to you, it wil be easier.
It is best to read new and somewhat difficult content on a computer to take advantage of online dictionaries and other new learning technology. Whatever you do, there is no substitute for learning in context through lots of reading and listening.
If you can find audio for these texts you wil find it even easier to read more difficult texts and to remember the new words and phrases.
As I am reviewing one of my old Korean books I am reminded of al the things that textbook authors do to make it hard to learn languages.
Most textbooks introduce vocabulary in categories. The names of the colours, or the parts of the body etc. wil be introduced together. Words that mean similar things or opposites wil be introduced together. So the vocabulary list for each lesson includes no t only what I need to understand the text in a given chapter but a lot of as yet unnecessary words that the author thinks wil help the learner.
In fact this does not help. Research has shown that it is more difficult to learn new items in such categories or associations. We end up confused. The brain does not remember them.
We learn best when we can get a clump of information, or a few new words or phrases together with a lot of familiar material or content. If we know al about flowers and are reading about flowers then a few colors or names of flowers can be absorbed as part of reading and hearing about interesting content.
A long list of the names of flowers or colors, on the other hand, is very difficult to learn.
Most facts or concepts that are taught in a way that is separate from real and interesting language content are not easy to remember. That goes for grammar explanations as wel .
There are courses on academic writing and on business writing. For people who already write correctly and wel , these might be helpful. For people who lack sufficient control over the words and phrases of the English language, these courses are misleading.
There is only one kind of English prose; clear, concise and wel constructed prose. If you control the words and phrases of the language it is easy to learn how to start with a "theme sentence" in every paragraph and the other little conventions of writing that are taught in these special writing courses. Without the vocabulary you do not have the resources to express yourself effectively.
Once you have brought your vocabulary up to the required level, read everything you can find on specialized writing. Start looking on the web where it is available free of charge. Or just buy a book on the subject.
Among the many fads in the world of English language teaching is the idea that English is no longer the language of its native speakers. The native speaker does not matter. English belongs to the world. You should be just as happy to learn Indian English, or Spanish English as American English.
I have real trouble with that one. Being able to speak to the native speaker, or listen to or read authentic native language content, is what attracts me to learning any language. If I am putting effort into learning Russian, it is to be able to speak to Russians, to visit St. Petersburg or Moscow, and have a beer or a vodka with a local. I want to speak an Indian language with an Indian, and Spanish with a Spaniard or Peruvian. Is it so different for learners of English?
Another concept that I do not agree with is the idea that a person need only learn a smal number of words in a language. Or the idea that you can memorize a few key phrases to look after most situations you will meet in the new language. It isn't that simple.