The basic principle of listening is to listen more and practice more. Talk more and listen more first. Special emphasis should be placed on dividing the listening time into several parts. Just listen to English as long as you have time, and it's okay to take MP3 with you-listening to songs is also listening. As for the choice of listening materials, if the foundation is weak, then start listening from VOA Special English, and gradually use more difficult materials after proficiency; If the foundation is acceptable, you can use BBC, CNN and other materials. Actually, you can do a test before choosing. If you can hear every word of VOA Special English, congratulations, just go to the BBC. Otherwise, start with Special English and listen to it in a down-to-earth way. Take some time out every day, and you will find yourself listening for hours. If you study, I suggest you go to Shanghai New Channel School. I feel that they have done a good job in IELTS training.