How can I improve my ability of listening？

Listen to more English News on television and radio.
Switch On English songs and listen everyday. If possible
read the lyrics too. Sharpen your listening skills.
Speak more English and during the test, be calm.

Enter the Exam/ Test Room. Relax, take a deep breath.
Be confident, you can do it:)

Listening skills can many at-times be a big problem but there is nothing impossible. If you try to be a good listener, you can be a very good listner. You can keep in mind these tips.
>>Accept the fact that you are not going to understand everything.
>>Keep cool & stay relaxed when you do not understand, even if you continue to not understand for a long time.
>>Avoid being distracted by environmental factors.
>>Stay Focused
>>Listen to the speaker’s body language if possible
>>Do not translate into your native language if your native language is not English.
>>Listen for the general idea of the conversation. Don't concentrate on detail until you have understood the main ideas.
>>Refrain from side conversations when listening in a group setting.

I think these are some basic things to keep in mind & you can definitely improve your listening skills.
Happy Lotting