So Mansoor you are from EL&CE. Well See as I told you in reply of your previous post. kindly follow my reply. 

Now i know your branch, I can tell some things .You can first study all of your subjects of EL&CE,take a brief knowledge of all of them then you can go for a question bank of EL&CE from GALGOTIA publications. It is really good. As psus always repeat their question time to time and this book contain lots of question of different PSUs of Different years. So you can go for this book.

For any thing else ask me