How can we learn English well? A student can know a lot about English, but maybe he can't speak it well. Why can't we speak English well? Because we don't often use it in daily life.
If you want to know how to swim, you must get into the water. And if you want to be a football player, you must play football.
So you see, you can learn English well only by using it. You must listen to your teacher carefully in class. You must speak English with your partners and also write in English. Don't be afraid to make mistakes. You should try to speak English with some foreigners (外国人). Then one day, you may find your English is very good.