Practice, practice, practice! I wouldn't bother with buying the books, I found the best stuff oNline
I booked mine for 4 weeks in advance and did a bit of study every night. Probably a bit of over kill as I needed 7 or 8 and ended up with 8.5 (and English was not my best subject) but still really helped me out with my visa points. Still a bit of joke that we have to do a 3 hour exam! I would spend the most time on reading and writing, listening is easy and speaking you cant really prepare for, its just a conversation with the examiner. Good luck!!
Harry