Here's some advice to help you avoid common mistakes in IELTS writing task 1:
- Don't copy the question for your introduction. You should paraphrase the question (i.e. rewrite it using some different words).
- Don't forget to separate your paragraphs clearly.
- Don't forget to write a good summary/overview of the information. A quick one-sentence conclusion is not good enough. I prefer to put the overview straight after the introduction, and I try to write 2 sentences describing the information in general. You won't get a high score if you don't write a good overview.
- Don't describe items separately (e.g. 2 lines on a graph). You should always try to compare things if it is possible to do so. Instead of describing 2 lines separately, compare the 2 lines at key points.
- Don't try to describe every number on a chart or graph (unless there are only a few numbers). A key skill in task 1 is being able to choose the key information and describe or compare it well. I usually mention around 6 or 7 numbers in my main paragraphs.
- Don't spend longer than 20 minutes on task 1. Practise spending 5 minutes on each of your 4 paragraphs. Stop yourself after 20 minutes; remember that task 2 is worth more marks.