First of all, you'll want to perfect your pronunciation ASAP. As far as vocabulary, every time you hear a word you don't understand, simply ignore it and allow the context to give you the meaning. Continue to pay attention, and avoid getting distracted.

Be careful with just reading or writing, however, because you won't get a sense of how words are pronounced, especially in English where spelling is of little assistance in that department.

There is no secret to listening well. You need a large vocabulary. If you hear an unknown word every five words, there's no way you can pick up the sentence. Every unknown word momentarily disorient you. You must minimize the unknown words. So I would say the thing to do to improve your listening is to absorb lots of words and phrases. Reading a lot so you acquire a wide range of words and phrases is the key. There's no short cut or secret.

Try to find movies or television shows to watch in English! You can also watch videos on YouTube or listen to the radio.