How to improve spoken English and written English ?

You have written this really well. I don't really know what suggestions to make but I hope others will be able to suggest helpful strategies. As Hanna C says, watching films and TV shows should be helpful.

Hi! I am also not a native English speaker! I took an english class for about 2 years and learned a lot! But what really made the difference for me was to watch movies and tv series in english with english subtitles. This will help you to see how the words are written while you listen to their pronunciation. Also, you could watch some good reality tv shows, because the language is more informal, so you will learn some expressions and slang words! Doing this will help you get used to the flow of the dialogues! It is really useful! Lastly, participating in forums is really good because if you have doubts on how to write something, you can always search it before posting your text. Doing this will help you fix it in your mind! From my experience, this really gave me a boost! My english isn't perfect, but I'm getting there! Hope I helped you!

your English here looks fine and writing on sites like this will always help your work. Read works of English literature too - good luck and welcome to Mylot

I'd say living in an English-speaking place would definitely push non-speakers to learn very quickly by the necessity of adapting to the new environment... I understand it's not always possible but taking intensive courses, practicing as much as possible, listening to movies or TV series, or reading in English would definitely help especially with the written part...

I am not native english speaker too that's why some netizens sometimes misinterpret my words We have english subject in school but I didn't get good grades I only excel in Algebra

That's also my problem, i'm literate in English language i have to think first before i can response to the one i'm talking to.maybe i'm not a reader that's why i get empty.