Writing down everything you know about a topic won't make a good academic essay. Analysing, then answering the essay's question or task is central.
Be sure that you understand exactly what the question requires you to do.
Identify the key words (like discuss or analyse) and clarify the approach you are required to take.
Work out your initial thoughts and ideas about the topic and write a quick, preliminary essay plan to help guide your research.
An essay plan can help you work out how you will answer the question and which information you will use. Essay plans also help with structuring an essay.
Remember, your plan at this point is provisional. As you begin to write and research it will probably change.