There were 2 rounds. First round consists of aptitude questions and second one technical test.
Aptitude was easy. You can practice it from various sites like pariksha, india bix, testbook, etc.
For technical, you should be clear with basics of few important courses like
thermodynamics, solid mechanics, fluids, machine design, etc.
It was a technical round. It started with the most expected question from the panelist, tell me about yourself and also add favourite and least favourite subject. Here I got an opportunity to introduce my internship project which was on heat transfer. Later panelist has asked questions. Most of them from heat transfer, a few from fluid machines. I answered almost all of the questions.
Started with tell me about yourself. Then he asked about my role model and later about location contraint.
One must be well prepared before attending any interview for some basic questions like tell me about yourself, strengths, weakness, role model, where do u see urself in next few years, etc. Here you will be getting opportunity to grab panelist's attention. your interview will depend on how u frame this questions in most of the cases.
Also you need not to be good at every subject. You should develop skill to take panelist in your zone.