IELTS Writing Task 1: introduction and overview

Let's look at the first two paragraphs of my sample answer for the question below.

The graph below shows the amounts of waste produced by three companies over a period of 15 years.

 

Introduction (paraphrase the question):
The line graph compares three companies in terms of their waste output between the year 2000 and the year 2015.

Overview (two main / general points):
It is clear that there were significant changes in the amounts of waste produced by all three companies shown on the graph. While companies A and B saw waste output fall over the 15-year period, the amount of waste produced by company C increased considerably.