Many students get very anxious when they are taking a big test like IELTS or TOEFL. The test costs a lot of money, and the results are very important. It can be hard to sleep. Stress will make it much harder for you to do well on a big test.
I recommend the relaxation MP3 files by Glenn Harrold to help you to relax and sleep well, while you prepare for a test or interview. I often listen to these files when I’m travelling, or if I have trouble sleeping.