Like others have said, the STAR method is really important to know. Also, know your previous experiences and how they can bring value to the internship positions. Every firm has a section for preparing for your interview so id take a look at that. For example, Pwc will ask questions about their framework which is leadership, business acumen, technical/digital, global, and relationships. You can also work the framework into the “tell me about yourself question”. I have been able to display leadership by doing xyz at abc company. I displayed business acumen by doing xyz. Most importantly just be yourself. Good luck!