Starting to write without first understanding the essay question.
If you do not understand the essay question(s)
it is very difficult to complete Task 2.
Writing long body paragraphs.
If you write only two body paragraphs you need to write 90 to
100 words per paragraph and describe more than one idea per paragraph. Long paragraphs do not work very well for the IELTS
Task 2 because they are not usually very coherent.