Exam related

hello members, my cafinal attempt lies in May 2015, I have not joined any coaching yet and have studied only few chapters of costing and sfm, I have to give both groups in may and want to clear in 1st attempt with good marks, I will get 3 months leave from my firm before exam, please let me know if there is any strategy for preparation. and also when to take coaching for DT and IDT. thanks