If I were you, I'd watch some English films 24/7. I guess it would be funny to watch the same film like 20 times until you know it by heart in order to speak with the protagonists

Whenever you take a shower or are alone in some room, start to sing an English song as authentic as possible.

To be honest, English is all about sprachgefühl (yep this is according to LEO an English word similar to feel for language). But this sprachgefühl is not easily learned in some days.
It is rather a long-term process in your educational life. Either you accept the language, you practise it in everyday life and adapt more and more to it or you don't waste many thoughts about it and stick with your mother tongue.
This is the easiest way, chosen by most people.