Understanding the task
Before writing your composition you need to understand the task, or the instructions, or the rubric as the task is also called.
We must read the task carefully and make a note of the key words and phrases which tell us what we must write about.
In the task (or composition instructions or rubric) we will usually have to distinguish four different components:
1 The imaginary situation you will write about. This can suggest who you are and what has happened: You are reporter who has to inform about a recent accident or report in your town.
2 The imaginary reader who is going to read your piece of writing: The manager of the company you work for has asked you to write … This will help you decide on the required writing style (formal/neutral/informal).
3 The type of writing, i.e., a letter, an email, an article, and so on.
4 The specific points you should include in your piece of writing (write about the advantages and disadvantages of keeping a pet in a flat).
5 The number of words in your composition.
Examples:
(1) You work for a travel magazine. (2) You editor has asked you to write (3) an article discussing (4) the pros and cons of air travel, including factors such as cost and convenience. (5) Write 120-180 words.
(1) Your (2) best friend is (1) spending the summer in Spain and needs advice. (3) Write a letter (4) advising him where to go and what to do and telling him approximately how much money he should bring. (5) Write around 150 words.
(1) You are a writer for an international English-language magazine. (2) Your editor has asked you for (3) a short article about (4) a famous person from the twentieth century that you admire. Write your article about the person, (4) describing his/her personality as well as the reasons why you admire him/her. (5) Write 170 words.
Most of the information on this post comes from Successful Writing Intermediate, Express Publishing.