Source: http://sas.calpoly.edu/asc/ssl/tests.essay.html

Preparation
Essay or subjective exams may include either short answer questions or long general questions. These exams have no one specific answer per student. They are usually scored on an opinion basis, although there will be certain facts and understanding expected in the answer. The main reason students fail essay tests is not because they cannot write, but because they fail to answer the questions fully and specifically, and because their answer is not well organized.
Essay exams require recall learning. Carefully figure out the major content areas to learn. If you are not caught up, this is not a time to read everything in a frantic manner. Focus on the key source for the test: notes or textbook, or whatever you think will be most heavily covered on the test. It's better to understand and know a few things very well than to have a large quantity of unorganized, poorly learned material. These suggestions may help:

1. List all topics sure to be a part of the test. List important subtopics for each.
2. Skim all the materials to be covered, checking those to be more intensively studied.
3. Write down all the key topics covered in class and in your reading up until the test date (probably about 5 or 6 topics at mid-quarter and 9 or 10 at finals).
4. Read or reread all materials not understood; use a specific purpose when reading.
5. Develop a pool of information for each topic. Answering words like "who," "what," "where located," "how works," "key characteristics, " "cause-effect," and "examples" for each topic will help to cover the critical information.
6. Finally, take 2-3 blue books to class and a mechanical pencil that won't need sharpening. If the instructor specifies ink, take a pen with erasable ink.

Taking the Essay Test
Read all the directions and questions.

• Note the number of items, point distribution, range of difficulty, and time available.
• Jot down any immediate answers that come to your mind - lists, outlines, etc. Jot down any other key information you might forget.

Analyze the test question and divide it into its main parts and subparts.

• From the parts quickly construct a rough outline.
• Note the instructional words included in the question, e.g., compare or contrast.
• Use the outline as a "map" to answer the essay question. If you don't have time to finish the whole test, this outline may give you some points. More importantly, the outline helps you to stay focused.

Make you answer as specific as possible.

• If you know the answer, write only what you are asked.
• Avoid generalities.

Use part of the test question in your test answer at the beginning of the paragraph. This signals to the reader that you are answering this part of the essay here! This will earn you points.
Include an introductory statement at the beginning and a summary paragraph at the end.
Review your answers. Your essay is written under the intensity of a deadline, but it is graded under much more relaxed conditions. Allow sufficient time to check for spelling, grammar, omitted words, incorrect dates, etc. This is when you will be glad you wrote in pencil.

A Glossary of Essay Test Words
ANALYZE: When asked to analyze, separate (a thing, idea, etc.) into its parts to find out their nature, proportion, function, interrelationship, etc.
COMMENT: When asked to comment, you are asked to explore the impact and meaning of something; give a note in explanation, criticism, or illustration of something written or said; remark or make an observation made in criticism or as an expression of opinion
COMPARE: Examine qualities or characteristics in order to discover resemblance's. The term compare is usually stated as compare with, and it implies that you are to emphasize similarities, although differences may be mentioned.
CONTRAST: Tell how two or more topics are different from associated things, qualities, or events, etc.
CRITICIZE, INTERPRET, and REVIEW: Express your judgment with respect to the correctness or merits of the factors under consideration. Give the results of your own analysis and discuss the limitations and good points or contributions of the plan or work in question.
DEFINE: Definitions call for concise, clear, authoritative meanings. Details are not required, but boundaries or limitations of the definition should be cited. Keep in mind the class to which a thing belongs and whatever differentiates the particular object from all others in the class.
DIAGRAM, and ILLUSTRATE: Present a drawing chart, plan, or graphic representation in your answer. You may be expected to label the diagram or add a brief explanation or description.
DISCUSS: Examine, analyze carefully, and present detailed considerations pro and con regarding the problems or items involved. Often found in essays.
EVALUATE: Present a careful appraisal of the problem, stressing both advantages and limitations. Evaluation implies authoritative and, to a lesser degree, personal appraisal of both contributions and limitations
EXPLAIN, RELATE: Clarify and interpret the material you present. State the "how" or "why," reconcile differences in opinion or experimental results, and state causes if possible. In brief, tell how it all happened.
JUSTIFY, PROVE: To justify your answer, provide factual evidence or logical reasons. In such an answer, evidence should be presented in convincing form. Establish your answer with certainty by evaluating and citing experimental evidence or by logical reasoning.
LIST, ENUMERATE: Present an itemized series or tabulation. Be concise.
OUTLINE: Give main points and essential supplementary materials, omitting minor details, and present the information in a systematic arrangement or classification.
SUMMARIZE: Give the main points or facts in condensed form. Omit details, illustrations and examples.
TRACE: Give a description of progress, historical sequence, or development from the point of origin. Such narratives may call for probing or deductions.

Bibliography
Deese, James and Ellin K. Deese. How To Study (3rd ed). New York: McGraw-Hill, Inc., 1979.
Examination Skills and Techniques. Lincoln, Nebraska: Cliff Notes, Inc., 1968.
Millman, Jason and Walter Pauk. How to Take Tests. New York: McGraw-Hill, 1969.
Pauk, Walter. How To Study In College (2nd Ed). Boston: Houghton Mifflin Co., 1974.