The most important thing is to listen, and that means as often as possible. The next step is to find listening resources. This is the point where you find that internet can be your first place to find tons of listening exercises material. You can try BBC English Service or other resources. I bet you can find them easily.
Once you have begun to listen on a regular basis, you might still be frustrated by your very limited understanding. What should you do then?
Well, try these:
- Accept the fact that you are not going to understand everything.
- Keep cool when you do not understand - even if you continue to not understand for a long time.
- Do not translate into your native language, just listen.
- Listen for the general idea of the conversation. Don't concentrate on detail until you have understood the main ideas. Those details would distract you to understand the whole point. That’s why you can fall to omit the idea of the conversation.