To create a proper expository essay do the following:

• Write a thesis statement. It should be accurate and brief so that you can cover it completely within your essay.
• Decide on the method for disclosing your case. It can be a good example, or cause and effect or even compare and contrast method. They all may drive a reader to a proper conclusion if used correctly.
• Analyze sources, but put the summary into sentences stating your own attitude and opinion. This is exactly what matters to your tutor.
• Formulate evidence in topic sentences and develop ideas, dividing them into separate paragraphs. Use clear and simple language. Avoid redundant adjectives and adverbs.
• The summary should restate the thesis sentence with the necessary definition that you formulated during the research. It should leave the reader with an impression that the topic is fully covered.

References and quotations are quite possible to use if they are to the point and give additional light onto the problem. Try to make each sentence give a comprehensive explanation of a problem. Choose the style and the format to your liking but remember that the main task of any writer is to make a reader interested in the topic and its progress.