Where do I start?

You start with the prompt.

That is the little blurb telling you what the writing task is, the instructions.
For Example:

"Analyze the specific reasons you prefer to ride the bus to school rather than walk."

or

"First describe the important factors a buyer must consider before buying a new car and then evaluate the car's most important safety features by concentrating on the most challenging aspects of that car."

Before you do anything, write a single word or read the provided essay or reading assignment, look at what the prompt is asking you to do. Look at the academic words (in bold) used in the prompt.

When I get a paper with a writing prompt, I always underline them so I am sure to understand what the writing assignment is asking of me. If you are doing an in-class writing test or assignment: Write down the words. You can even use those specific words or ideas when you are brainstorming. On occasion I have even used those specific words or ideas in my introductory paragraph.

Definition of Academic words:

Analyze: Break down the subject into parts and then explain what is the difference and how they might be related to each other.

Compare: This will be between two (2) separate things. You will show how they are similar as well as how they are different with details and examples. (If it is more than two things, you will be expected to rate or give value.)

Contrast: This will be between two (2) separate things but you will focus on how they are different with details and examples.

Critique: You will point out the good points and the bad points of the thing.

Define: Give a clear and accurate meaning of the subject, and provide details and examples to show that you understand the subject.

Describe: This providing a visual detail of the subject. You will tell how it looks or how the even happened. You will also provide the Who, What, Where, Why and How.

Discuss: This is asking for a complete and detailed answer which will include the main points and the important characteristics of those points.

Evaluate: This is asking for you to give value or importance of the subject. You must talk about the strength and weaknesses, the good and bad points. You are suppose to give examples and details, but you are making a judgment on its value--opinion with proof.

Explain: You give the meaning of something with facts and details to add to the understanding of the subject.

Illustrate: Make the idea you are presenting by giving clear examples.

Interpret: Explain the meaning of something you read, or discuss the results or effects of something you observed.

Justify: Give good reasons to support a decision, action or event.

Persuade: Give strong reasons in order to get someone to do or believe something; appeal to the reader's feelings and mind.

Respond: Give your overall reaction to the material read, then support your opinions with specific details and examples, always referring back to the source of your reaction.

State: Give the main points in brief, clear form.

Summarize: Just briefly cover the main points of the subject. In this response you do NOT include the personal opinions about the content.

Trace: Tell about an event or process in chronological order.