hi laxmi,
i have also gone through the same situation in past 2 attempts, one suggestion is that now we can apply for copy of verified answer papers, the same has been upheld by the RTI commision(find refference below).
may be you can apply for the paper which has been stumbling block for you to achieve what you deserve and can improvise your performance in the coming attempt and have that smile on your face ;)
about preparation i think it would be better if you get the paper and then compare with the suggested answers of the institute which will help you know where you stand. there on it should be easy for you to move ahead in the right direction with a greater speed
Name of the Public Authority: The Institute of Chartered Accountants of India ,
Decision No.4167/IC(A)/2009 ,
F. No.CIC/MA/A/2009/000474
all the very best for your planning and coming attempt.
"Hard work never fails, but sometimes luck plays"