In fact that post was because of a question sent to me by Email, so I took time to answer in a short post to help more than one person.
That person resent me another Email telling me some details that I asked. In the second Email he said:
"I'm at the high school now after 2 years i will join the university and i will study for 4 years during this 4 years i will improve my English well"
I think you have so much time to improve your level. While I always advice to not study English grammar, for your case I do recommend studying English grammar very well, because you're not going only to speak English, you're also going to teach English and especially "English Grammar" (I know in schools they force teachers to teach English grammar even if it's not good enough)
In the next years, you should focus on your English learner a lot, you're not a normal student because you're going to become an English teacher in few years.
You have to study twice: normal studying as your colleagues, and some secret studying that you'll do alone at home.
At school you should focus on what your teachers are teaching you, while at home you should focus more on listening and improving pronunciation (I know teachers in your countries don't have a good accent!).
Another thing that you must have is a "huge vocabulary" in your brain, you should know a lot of word lists (I do not recommend that you memorize).
Yes, you can do it without memorizing, it's so simple to have a huge word list deeper into your brain but you should take time to do it because it's not going to be done overnight.
Focus more on listening, it's the only secret: students who listen to English more improve their level faster... (that's the rule!!!)
If you have a problem with vocabulary or you can't find the right word when you try to speak, you should start with basic English vocabulary first then do some simple English readings and then go to some more complicated words...
Listening should be with you all the way, from beginning until becoming an English teacher (even if you become an English teacher you should go on listening to English).
And finally, I hope that you'll become an English teacher and you'll send me an Email telling me the good news.