how to study for Toeic

I am in other country to study English for a year. I cannot type in Japanese.
I need to take toeic and get 850 on this December, when I come back to japan. My score is 560 now, reading and listening is same score. I don't know how to study for it, so please give me some good advice for me if you have toeic high score or good knowledge of it.