I disagree with not saying “I don’t know”. I’ve interviewed people who refuse to say it and it’s pretty easy to tell. And I’ve worked with people who don’t know something and are afraid to admit it - often at the 11th hour, they have to be rescued. It’s pretty aggravating IMO
Ultimately, I’d want a team member who was comfortable with admitting that and then had methods to find the answer.
I generally read through my resume and prepare extended blurbs about the projects/responsibilities I’ve written about - after all, that’s really all they’ll know about me at first.
Then I think of more detailed things throughout my career so far that wouldn’t be resume-worth, but that I’m proud of or learned from or whatever. Just to have a bit of a script for that side of things.
I make sure I’ve got good enough answers for the basic interview questions: biggest strength, weakness, hobbies, projects outside of work (and why I don’t do them), best project, worst project and why, etc.
I try to have 2-3 questions to ask them at the end. Sometimes I don’t really have many good ones, so I make a note to make some during the interview itself - asking about tech stack details is usually a good springboard. And I genuinely will make a note to myself to remember that because I know that I can flip into autopilot and not be very chatty.
The rest for me honestly is just rehearsing that basic script enough to let it flow casually so that I can spend my energy on listening and interacting with the interviewers (and being in a good headspace for any technical questions that pop up).
When I’ve not done that step, because of the nerves from being on the spot and with new people, I tend to come off kinda stuttery and unsure of myself. And it’s all about confidence, babyyyyyyyy
*Edit: this is interviewing for a job where I’m comfortable with the roles and responsibilities. If I wasn’t as confident in my abilities, I’d also spend significant time doing general studying on those parts. But I’d also be ready to say that I didn’t know something yet, but I have a track record for being a fast learner, such as when I blah blah blah…
I got “humanoid…made… extremely polished”