Trouble during oral exam and composition.

Recently i had a oral exam and composition test,and i got a low score for both.
During oral exam,i feel that the way i pronounce is not smoothly enough.During conversation,i had trouble expressing my thoughts and ideas.I will be like keep worrying how i will fail the exam. I always give ideas that uses basic word and short sentence,so as to not show my weakness in english skills.After the oral exam.when i am calm.I am able to think of much structured and interesting ideas....
During composition test. I have no interesting storyline. And somehow my essay always is in red underlined( my expression and grammar)

Somehow i really want to improve my language skills,and do well in both exam genre. Any tips on how to improve language skills fast?? While reading a book,what do you need to take note of???