Good question. I can relate.
Some of my interviews gave me a tough time especially if they were big companies. You can check out these steps, they will definitely help:
- Learn as much as you can about the company
- Know more about the job description
- Practice interview questions
- Ask the interviewer some questions to show your interest in the company
- Dress appropriately
- Don't get to the venue late
- Be positive and confident

I wish you success in your next interview