To be very honest, FCPS 1 in Radiology is easiest of all the other specialities in my view. Reason is you are very selective and you have to grip few things out of many.
Now there are 3 ways to pass exam.
1. Either you are smart one.. (Not always Best) 2. You are a hard worker.. (you will get fatigue trust me, since course is so long) 3. Both.. (For me its best.. you should have a touch of both)
Now.. Coming to Subjects and How to prepare.
Again most important FAQ is how many hours to study and for how many days.. Its very simple, it depends on your capacity, learning power and Stamina. For me i think 12-14 hours a day for 2.5-3 months is enough for those who are appearing for first time.
Second, If you have failed. Then take a small rest (1-2 weeks may be) to regain your stamina and to regain your energy. You will easily do in 1.5-2 months now .