First, you should listen carefully in class. It's very important. Second, you should do your homework carefully after class. It is necessary for you. Third, you should practice your listening as much as you can, You can listen to the radio more. It's a good way to practice your listening. Finally, you can go to the English Corner to practice you oral English.
As the saying goes" Rome wasn't built in a day' If you can do all things above. Keep moving, never give up. I believe your English will get better soon.