The central thing to keep in mind when approaching the creation of a essay question answer is the primary function of the question: to afford you the opportunity to demonstrate your understanding of the information by applying it to the construction of your answer.  You should draw upon the information reviewed in class to form the foundations of your answer not simply present your personal opinion.  Make sure you answer all parts of the question fully and your answer is properly organized.  Make sure you define all your terms.  Make sure you illustrate your key points with detailed examples.  Make sure your answer is in your own words.  Answer length will vary depending upon writing style and the question chosen, but generally I expect between one and a half pages to three pages.  I expect the answer to be written in a neat hand and to be legible.  Remember this is an essay question not a short answer!