It sounds kinda cringe, but I actually have found spoken mantras to be really helpful. Like, you actually have to say out loud that you are good enough for the position, that you know what your doing, that you are capable of nailing this interview, and whatever else you find personally helpful.

It sounds dumb, but it totally works and puts me in a much better place mentally before an interview.

As others have said, practice some answers, again out loud. Get comfortable saying the words. Don’t memorize lines, cause that ends up coming off a little robotic, but just try out some different ways of answering common questions.

As for general interview advice, I try to ask as many or more questions than they ask me. This way, I can kind of steer the conversation where I want it to go. I find this is the easiest way to get to a conversational cadence, which is where I want to be because I know the subject really well and I actually am pretty passionate about it.