It is important to understand what an essay question or assignment brief is asking of you. Before you start to research or write, it is worth spending time considering the wording of the question and any learning outcomes that may accompany it. Failure to do this could in an unfocussed response which does not answer the question.
Before you start to research, plan or write:
Check the word count, deadline and any guidance from your department
Read through any learning outcomes or marking criteria
If there is a choice of questions, make some initial notes on each one (or a few that appeal) and make a careful decision
Unpick your chosen (or given) question and ensure that you understand exactly what it is asking you to do