There are a bunch of websites that list interview questions. You should practice saying them out loud at home. That helps me with the anxiety because it's weird to talk to yourself at a normal volume. Once you get used to that you're a little stronger facing other people.

As others said, the best thing you can do is force yourself to be super cheery, especially in the panel interview. Likability usually trumps technical knowledge for entry or mid-level jobs.

Don't freak out about the manager title either. A lot of companies hand out titles like candy, sometimes so they can pay you less.

You can also research online questions that you can ask your interviewers. One good question can show your passion for your field or interest in the company.

Practice is the best thing you can do to help your anxiety. Good luck and I hope you get a job that you love!