I am no test-taker, but I think you can build vocab. By reading some good books (on a budget - perhaps you can buy some book at some second-hand store near you).
There are some FCE sites as well, you can see what topics are frequent and you can rush to the books. I will see if I find some book on writing, if I find it around here I will let you know.
One good thing is practice, you can post your writings to be proofread.
As for the listening, there are podcasts around here, on the VOA site and others. In your leisure time you can watch some Youtubers with good English (Nienke Helthuis, for example).
Just don´t get caught up with the fun to the point of forgetting the studies, ha ha!http://www.tinyteflteacher.co.uk/learning-english/FCE/sosuch.html
Here, for example, you can see that a topic to study is the pair SO/SUCH.
You would also notice that there are expressions, collocations, word formation, etc, all of this could be in the test. So being on the site is an indication that you should learn them.