If you plan properly and stick to that plan, whether you like it or not and no matter whatever happens, even 4 months of preparation is very much enough to crack the exams and even get a rank.
"Take up one idea. Make that one idea your life - think of it, dream of it, live on idea. Let the brain, muscles, nerves, every part of your body, be full of that idea, and just leave every other idea alone. This is the way to success."
Else, even 4 years won't be sufficient.
Most importanly, what I've learnt is that I should develop a liking towards the studies. I shouldn't force myself to do it. Studying should be fun.
Have fun mate and good luck.
