Practice.
WHAT TO DO
"Here is the job advert. What are the ten most likely questions?"
Then practise each.
FOR PRACTICE
"Ask me interview questions one at a time. After each answer, tell me what was weak."
Genuinely useful and costs nothing.
FOR STRUCTURING ANSWERS
"Help me structure this experience into a clear answer of about ninety seconds: the situation, what I did, what happened."
WHAT TO PREPARE YOURSELF
Your actual examples. The model can structure them; it cannot supply them.
Three or four examples cover most questions.
QUESTIONS TO ASK THEM
"What should I ask that shows I understood the role?"
FOR DIFFICULT QUESTIONS
Gaps in employment, leaving a previous role, weaknesses.
Preparing an honest answer beforehand is better than improvising.
WHAT NOT TO DO
Memorise generated answers. They sound memorised.
Prepare the substance, then speak naturally.
AFTER THE INTERVIEW
Draft a short follow-up. Most candidates do not, and it is noticed.