4) Read, watch and listen to English in many different contexts.
If you only watch news programs in English, then you will be able to understand a more “formal” style of English, but not a typical conversation between two native speakers, which is often filled with idioms and slang.
On the other hand, if you only watch movies and listen to songs in English, then you might not be able to understand (or write) a more academic article. And if you only useEnglish for work, then it will be hard to talk about other topics because you won’t have the vocabulary.
So make sure to diversify your English input:
fiction and non-fiction
formal and informal
lectures and conversations
serious subjects and comedy
etc.