I will second what Moona said. If i had my time again, i would have done all of my exams before i left the UK. I did 2 exams before i left and a lot of studying. Buy the books atleast a few months in advance to get a "grounding" knowledge and it may also be a good idea to have atleast an hour in the air to put all of the theory into a practical scenario. It helps!
I think alot of people forget about the other stuff you need to learn. BUMFICHH, HASELL etc. oh, and emergency check lists! A lot of work in a short period of time!
Do your homework and you will achieve what you set out to achieve!