How much studying is necessary for the mocks/junior cert?

its the 28/1/12 y mocks start on Thursday the second of Febuary (just business though), anyway I wan't to do quite well but I wan't too know (mostly by people doing the JC this year or who have recently done it.) how much study I should do for the mocks/JC. It might help if I add my Christmas test results.

Business - 76% (B)
English - 78% (B)
CSPE - 97% (A)
Irish - 63% (C)
French - 86% (A)
Geography - 63% (c)
T.G - 78% (B)
WoodWork - 80% (B)
Maths - 55% - (C)

My main subjects I find diffucult is Irish and maths, mostly Irish (I know I did better in Irish than maths but thats because I left my maths notes in schol before the exam )

Thanks guys.