Task 1 introductions should be fast and easy. Just paraphrase the question statement (rewrite it in your own words). If you practise this technique, you will be able to start the writing test with confidence.
Look at this question statement from Cambridge IELTS book 2, page 95:
The table below shows the figures for imprisonment in five countries between 1930 and 1980.
I'll change 3 elements of this sentence:
1. table shows = bar chart compares
2. figures for imprisonment = number of people in prison
3. between... and... = over a period of
So, here's my paraphrased introduction:
The bar chart compares the number of people in prison in five different countries over a period of 50 years.