Your question is “I want to do any PSU job as an engineer through GATE exam. Please kindly give me some advise about it. How can I fulfill it?”   Full form of GATE is Graduate Aptitude Test in Engineering and it is supposed to test the understanding of various subjects of Engineering & Science. Note the word understanding. So the basic requirement is to develop the proper understanding of the subject. In colloquial language it is called “funda” meaning going deeper into fundamental. This is certainly time consuming but that is ultimately the goal of learning. Any knowledge gathered is finally for application in real life. That requires skill development by training and practice, by solving as many known problems as possible exploring every aspects of the concerned subjects. Not succeeding in solving a particular problem compels you to go back to further understating of the subjects. The getting deep understanding of a subject and developing skill to apply the knowledge in problem solving is an iterative process. The first part of the process is mostly studying right books of high quality and getting guidance of teachers. The second part may be aided.  Because of popularity of GATE examination, numerous helps are available which are targeted towards problem solving skill development. I understand most students are aware off those aides.  I have nothing much to add to. After getting employed in PSU one must not get complacent with relatively high security of job it provides. To grow as professional in life the process of learning should get prime importance, be it the domain of your work but also the allied fields.