Brainstorm ideas. For each of your potential essay topics, make a mind map or idea list and jot down everything you can think of that might go in the essay. Don't be afraid to let yourself get a bit off track; sometimes these detours lead to the best ideas. Do a bit of preliminary research to see if there is enough material.
Choose your best topic and make a topic sentence that is specific enough that you can cover all the important points within your page limit.
Research your chosen topic and take notes.
Write an outline of your essay. Follow the given structure of the paper (argumentative, discursive, comparative, etc.) and for each paragraph, write the topic sentence and a few points from notes about the content.
Write the body of the essay first. It seems more logical to start with the introduction and go through to the conclusion, but it's actually easier to preview and conclude the paragraphs when they're already written.
Start the introductory paragraph with an interesting sentence that draws in the reader. Then state your topic sentence and explain why it is important --- this is where you can unleash your passion for the topic. Lastly, briefly outline your main points.
In your conclusion, summarize your main points and try to show how they tie together to prove your conclusion. Show why your conclusion matters by putting it into a wider context.
Cite your sources following a standard format such as APA, MLA or Chicago.
Print out your essay to edit it. This is easier if it's double spaced. Go through and look for areas that are hard to make sense of, as well as spelling and grammar mistakes, and repetitive words. Use the thesaurus or your imagination to vary your vocabulary.
Leave it for a day or two and read through it again. Edit anything that doesn't make sense or sounds weird. You can also give it to a friend to read through and edit. Ask them to tell you what your main points were. If they can't, you need to clarify your paragraphs (or maybe get smarter friends).
Print the essay and hand it in.