Before you launch into an essay or assignment, it is important to consider the task or question that you have been set.
Ask yourself whether it is a broad or narrow question, and if it is broad, which aspect of it do you intend to focus on? Break down your question into its parts and make notes on each.
Consider how you will need to write; what limiting factors there are; what subjects you will need to read about. Develop these notes into the first stages of your assignment plan.
If you are unclear as to what is expected of you, check with your tutor or try discussing the assignment with your peers.