hazya, I was on the same boat but I am glad that unlike Vietnamese which I need to understand every single word to be able to understand what a sentence means, with English I need to focus on some key words to understand the whole things.
When I started learning English, my friends recommended me to listen to some short convos, then write down what I heard and checked it, back and forth. I gave up on that way very quickly cuz It was so boring and I watched movies which I like instead. I watched it with Vietnamese sub first, tried to write down new words and see how people pronounced words. Cuz it was the first time I watch those movies, so of course I got distracted by contexts. Then I watched them second times with English sub, this time I knew what those movies about already, so i paid more attentions to English. 3rd time I watched it without any subtitle, I guess this time my brain got used to with those movies, so I understood it more quickly.
I know my way takes a lot of time and it's kinda boring as well, but it worked because I like those movies, and it's totally okay for me to watch them over and over.
I think the best way to do something is doing it with your passion. Just find something which you are interested and then do it in English.
Finally, you know how benefit it is to be able to communicate in other languages besides your mother tongue, so learning languages is not an easy thing to do, it takes a lot of time and efforts because it makes you different from other people, so you need to be different from other people by trying harder than them a lot.