Choose a topic that has relevance to the subject of the course you are taking. You will want a narrow topic, because the purpose is to explore one aspect of the subject to its fullest, not to try to cover as much of a subject as possible. Narrowing your topic will help you research your essay. Part of narrowing your topic includes writing a working thesis. At this point, having your exact thesis will not be necessary, and you will find your thesis will evolve as you research and write.
Research your topic to help you expand your knowledge of the topic, while at the same time helping you to narrow down your topic. When you research, you should keep notes about what you read, and what your thoughts are as you read. Research using reputable sources, such as books by experts, quality newspapers and journals and scholarly websites. Compile a list of possible quotations and passages you will use to develop and support your essay. Make sure you research one or two opposing positions for you to counter in your essay.
Write a first draft of your essay. Do not worry about spelling or grammar for the first draft. The point of a first draft is to write a basic and coherent argument to develop your thesis statement. Each paragraph should address one point of your argument, with one paragraph presenting the opposing view and your counter-argument to that. Include an introductory paragraph to introduce your topic and present your thesis statement, and a closing paragraph to reiterate your points and restate your thesis as a conclusion.
Set your first draft aside for a few days, and then read it. Take notes on what works and what does not, and then rewrite it. Clarify your thesis and make sure your essay covers the thesis as well as possible. Remove any parts that do not directly relate to your thesis, and properly incorporate your quotes, references and sources. When it is finished, put it aside again, and then later edit it for clarity, spelling and grammar. Make sure you cite your sources, for quotations and paraphrased content, according to current Modern Language Association (MLA) guidelines.