For ISCA case studies, first try to follow case laws given in Mat & Practice Module. This will help u to build up your thought process & line of thinking in tune with that of the thoughts of ICAI. Also go through the old RTps having solved case laws. Hope this will give u enough confidence to tackle with the same.
Also try to build up a summary for each chapter, which necessarily highlights the main contents of each chapter, so that when in distress while deciding a case law, your thoughts can be restricted to the main contents of the applicable chapter , but in case u cannot decide on the finer points of the said chapter.
All the best, & keep your confidence level high. This is the key to success.