Mental preparations for interview questions isn't quite as tough as it seems. It's really a matter of understanding interview questions, and the reasons for them.
Some people are quite literally scared of interview questions, and the whole concept of interviews in general. The major problem is that interview questions are seen as threats. They're not. They're necessary, and they're the reason you get the job, when you get them right. They can't be both a threat and your reason for being there.
Other people are cynical about interview questions, because they don't seem to get jobs when they do interviews. They're good at their jobs, but lousy at interviews. You sometimes hear that interviewers don't make sense, or didn't seem to understand interview answers.
Occasionally, things aren't done properly, but that cuts both ways, particularly with interview answers deciding who gets the jobs. If you're not getting jobs, it could also mean you don't understand the interview questions.
Other people are getting those jobs, and they're answering the same interview questions.
If you've had interview training, you can use it to predict interview questions.
It's a predictable, list of interview questions in most cases. The interview answers may be more complex with a more demanding job, but that's also to be expected.
The job criteria are the reason you got the interview. Your application matched the job criteria well enough. The interview questions will be about subjects you do know a lot about. Your interview answers just need to be reviewed. The mental preparation is quite straightforward.
One of the reasons for a face to face interview is the need to check out actual personal skills. Good communications are vital. As an experienced person, you know that. You know how to talk to people on the job. That's the heart and soul of good interview communications. Your interview answers should be exactly what you'd say on the job.
Critically important, and you've done it every day on the job. Interview questions will be about things you do regularly. The mental preparation should include reminding yourself of that. Make sure your interview answers accurately reflect your teamwork.
Problem solving interview questions come in different forms, but have one thing in common. All jobs have their own problems. Mental preparation for problem solving questions is really remembering examples of when you solved problems for your interview answers.
Relationships might be internal or external, or both, depending on the job. As mental preparation, consider how your relationships work. Most interview questions are about things you know well. Your interview answers should really describe your work.
Really, mental preparation is more about reminding yourself of what you already know, than answering interview questions.