Here is the list of sources I use more frequently for self-education as well as for my students.
Let’s classify all of them into four main groups: grammar, pronunciation, and vocabulary. Practice and bloggers I cover next time. Let us get started.
I am an old-school guy. Therefore, I prefer to learn grammar, firstly, by reading texts and, only secondly, by watching videos. Here are mostly text-based sources.
I like this source for its comprehensive grammar content and absence of advertisement. The grammar here can be learnt by beginners and in addition more advanced students. The same situation is with its vocabulary cards where you can find lists with simple words and lists with proficient-level words.
How I use it: grammar articles for deep learning
Here is a very strong and well-cooked set of grammar exercises for more or less high-level students. There are also non-conventional explanations for some grammar topics. For example, you can learn Conditionals through the prism of what is real and unreal but not by name, like Conditionals 1,2,3, which are not memorable for many. Or another topic that has been developed here thoroughly, which you can also learn infinitely=), is Articles in English.
How I use it: grammar articles and exercises
This source includes a sophisticated index with various grammar issues. In its glossary, there are such rare terms as neuter, appositive, zeugma, determiner, ellipsis, homonym and many many more. Each term is a grammatical article with many examples from literature and real life. Some of the most popular articles have videos. So, if you want to discover English grammar in one place, Grammar Monster gives you all you need for the journey. Another big plus is that the website is free of advertisement.
How I use it: explore grammar topics in-depth
It is very tempting to click an audio version(s) of a word in a monolingual dictionary or, for instance, in Google Translate. But they give pronunciation without some context.
Free years ago, I found a very worthy service. The source title is created by a combination of two words: youtube and English. Its main goal is to provide real-life examples of word pronunciation. All sources have been collected from Youtube.
What can you get here?
First, speakers from Youtube give you pronunciation, not bot-generated but real, with highlighted target words in subtitles.
Second, you get the context. That is important for further application of the word/phrase in your speech.
And last is about accents. You can use filters for taking American, Canadian, or British English.
How I use it: check pronunciation, stress, or context usually in combination with monolingual dictionaries.
There are many online dictionaries, thematic lists of words, or apps you can find online. I use many of them but some of them I involve in my practice regularly.
There is one note about hoarding my vocabulary. I use monolingual language dictionaries in 95% of the cases. So, all my strategy on how to use dictionaries is based on this premise.
Why is the source here? When I meet a new word like a proper or common noun, that is, a name of someone/something, a historical term, or some modern phenomenon, I employ Wikipedia for the task.
You can use several ways to navigate Wikipedia for this purpose.
The first is predicting the spelling of a new word. If you have success, you can read a comprehensive article about the word with references.
The second approach you can use if there are no ideas on how to write some particular word in English. Usually, I switch to my native (Belarusian) language and type it as I know. Then I try to find an article in English by using the Wikipedia language menu. That is it.
Do not underestimate the way. It was essential for such domains as biology, physics or history in my case. Materials in Wikipedia have pictures, diagrams and many references.
How I use it: collect and process knowledge about special terms and modern domains.
The history of the source in my English tool kit is more than 7 years. You can find not only as many definitions of words/idioms in one place but also their examples. It is the main advantage in comparison with other dictionaries. What else, here, in the sister project freethesaurus.com, there is a hub of synonyms, antonyms, and their visualisation. What can be hard here is to choose the definition you need thirsty. Yep, sometimes it gives 10-20 or even more versions of explanations for just one word. But I like this list of alternative meanings.
How I use it: develop definitions, find synonyms, examples
The website helps to understand modern slang and Western culture.
It is a crowdsourced dictionary where people can add new, or vote for existing words and collocations. Usually, you can find several explanations for each phenomenon and choose the one that fits your needs the most. This platform gave me the understanding that a language is not a static construction but a living organism developing continuously.
What is more, after reading different variants there appears strong confidence that you can use any words as long as they help you to transmit some ideas to others and of course be understood by your audience.
How I use it: understand modern slang and utilise it.