First of all, do things step by step. It is no good to listen to anything beyond your level . Don't choose too difficult materials .
Secondly, stick to one course of study . Work hard at it until you master it well .
Thirdly, listen to the English news program over the radio every day. If you have more time, listen to some interesting stories, too.
There are many ways to improve your listening ability . It is up to you to find out best ones for you.