There are many ways to improve your language, but the best is absolutely practicing.
* Try to speak with native speakers and don't be afraid.Even the English make mistakes. If there be none speak it with you friends.
* Something else of major importance is reading, constant reading. This helped me so much. I sometimes find myself subconsciously writing some very complex structure .
Notice: U should have a copybook where you write down new vocab° (with full context) so that you can revise them from time to time.