Hello, I am not a teacher,
but in my mind, there is only one solution, practice, practice and again pratice.
I reckon you must begin by the basics English grammar rules, and after listen English, Americans or Australian radios or movies because all these countries have differente accent and obviously your understanding is going to be better.
Read a bit article each day which you like can also help you but you should have a dictionnary next to you for the vocabulary you will not understand.
Learn English it's like a tube you go into and after day by day step by step you see the light of the end of the funnel, but it is a long way.
Have a nice day.