How do you master a new language ? According to the website WikiHow, what you can do is :
1) Listen to the radio, so you can get used to the pronunciation of words and the intonations of the language.
2) Phone a friend who can speak this language, and talk everyday for an hour if possible.
3) Read, read, read, in order to widen your vocabulary and your knowledge of the language.
4) Think, try and formulate things in the foreign language.
5) Watch a film or listen to a song, this can be both pleasant and really helpful.
6) Write it down, try and fill a whole page with your thoughts, notes, projects using the language you want to learn.
You can find lots of other tips on the website WikiHow. And you can even write your own guide on a subject you master.

WikiHow Homepage
The tips may not work for everyone, but still, the website’s quite an interesting resource.