Not answering the question is a common fault. Underline key words and ensure you understand precisely what you are meant to discuss.
Frankenstein: AS & A2
Take a position on the question and then outline a series of key points for discussion, ensuring each point connects to the set question.
Make sure you pace yourself so you have time to cover all aspects of the set question.
Leave time to edit your answer, checking that you have stuck to the question and correcting any errors in spelling, punctuation and grammar.
Be prepared, but don't cram the night before. If you panic, breathe deeply and re-read the question to help focus your thoughts.