How to prepare for ca final second group in 1 and half month

study all 4 subjects everyday is the only option which create confidence.  

Set a daily target for AMA, DT and IDT. These subjects need more time. Try to complete them in approx 40 days. As far as ISCA is concerned, read 1/3rd chapter daily. In this way, you will be able to complete it in a limited number of days.
In DT... prepare assessment procedure part, case laws and amendments thoroughly.
In Costing... solve practice manual also for better practice.
In IDT... Don't ignore customs and procedural chapters.
Study case laws & amendments too.
If you complete your preparation in 40 days.. you will get about 15 days for revision as group 2 will commence from 9 Nov.
All the best :)