If you study hard and did not see improvement, then you need to understand 3 things:-
1, did you really know how to read the words in the word list, and understand their meaning, and know how to use then in a sentence! did you master at least 50% of the word list required by examinations?
2, Did you know all the scripts and know how to answer the different kinds of oral questions? Can you answer any oral questions in 5 seconds with no hesitation!
3, Did you read ALL the compo especially those well written ones well and study their structure and story line. Can you cook up any story using the hints in the questions and your imagination and write out every details of the story with accurate expression. Can you use detailed description of action, facial expression or verbal dialogue etc and/or analogy to make your story interesting.
Work on the 3 points step by step and your Chinese reslts will improve.