Here I am giving you some preparation tips for Public Sector Undertaking examination below :

You should start preparation start as soon as possible. You must give at least 10 to 12 hours per day for studies. it is also important that you must follow your studies timing strictly..

you must know complete syllabus and exam pattern of Public Sector Undertaking examination. You have to make notes for important topics for Public Sector Undertaking examination and revised them regularly.
For better preparation you have to solve the previous year question paper of Public Sector Undertaking examination or you can buy books for it .

Best books for PSU :
CA A.k.chakraborty
Digital Electronics Morris mano
Analog Electronics Milliman halkiyas
LIC ramakant gayakwad
Control I.j nagrath
Microprocessor Ramesh gaonkar
Signal system Hamid nawab.