Hii kannu 

Nobody is really confident that he will positively succeed in an exam where success ratio is very less. You should make your notes, judicial services preparations can informally start from the law school itself.

One should also cultivate s rational and reasonable world view and should be able to have independent opinions which are free from biasness. It requires 1-2 years of dedicated preparation if you have to start from scratch. 

Books you can refer-

• Ratanlal for Indian penal code
  
• Kelkar for Cr. Pc
• Takwani for cpc
• Avatar Singh for constitutional law. 

Hope it helps you