Essays are very much a personal style, but there is a very universal structure to each essay that you can follow to begin developing these skills.
INTRODUCTION
This needs to be concise and straight to the point whilst also covering the basics. You need to highlight what the question is asking you by defining any key terms or themes, briefly mention your major points and indicate what you think overall in response to the question. This will help channel your answer later on.
MAIN BODY
Depending on how many themes you have, your main body is divided into paragraphs. Each paragraph should follow the same basic structure:
Point - What is your point/theme for this paragraph? Be clear on this.
Evidence - What can you use to support your argument? Use quotes or close reference to the text.
Analysis - Why is your evidence relevant and what conclusions can you draw?
Then you must tie every paragraph back to the question.
CONCLUSION
Summarise your main points, and repeat your opinion. This should be slightly more detailed than your introduction but should not introduce any new material, evidence or arguments into your essay.