The Interview should not be the first time when you are facing the Interview!
Mock Interviews are a good way to practice for the real deal. They give you the experience of being 'in the interview'. They are like the Flight Simulator before a Pilot is put into a real plane to learn to fly.

They help you identify your blind spots (my recent Coaching client mentions in his testimonials that identifying his blind spots was the biggest gain from the coaching journey he took with me). The mock interviews put you in the hot seat and you feel the heat.
The poll we did last week to check how many mock interviews candidates went through before they went for their actual job interview threw up a startling result.
Two-thirds of the respondents picked ZERO as their response. And many out there did not respond to the poll simply bcos they would have had to pick ZERO.
So the number of people who are entering the interview room without any practice of the interview is humongous high.

Very surprising you might think considering all our school life and higher studies, we did mock tests and practice papers. They made the exams a piece of cake - more like 'been there, done that already' so no worries now.
So Mock Interviews are a must. The key here is the selection of the right people to do your mock interviews.
To warm up, you can ask your friend to do it. But to get some real practice (and solid feedback/evaluation post-interview), you need an experienced hand.

Connect with a professional coach or a mentor, or a past manager or alumnus from your institute who would be ready to spare 90 minutes to help you.
Share with them, the context of the interview and job profile, and ask them to put you through the grinder :) Ask them to share their feedback and evaluation at the end of the 45-min interview and suggest how you can become better.