Teachers have different teaching methods and accents. It is important to find the best learning style for yourself. However, you must listen different accents to improve your listening skills. Therefore, you should take lessons from different teachers.

I think you need to use your English everyday :-) This is the right way to improve each of your skills not only English skills:) It is my presonal opinion , I am still learning :)

What do you think, it is possible? 

My personal opinion, and I was a foreign language major in college in the early 80s, is the Pimsleur cd sets.

I am learning Egyptian Arabic with them and having enormous sucess.   You can buy them second hand for less money through Amazon or Ebay.

Best of luck to you.

you shouldn't focus on grammatical rules, you should focus on english listening and english speaking, watch english videos on the internet and use english everywhere, for example while working, walking, shopping etc etc..

Yes I can do it Marek ,thank you