I recently met Sally Newman from Positive Interview Preparation. Sally runs an interview skills service for young people – see the Interview Guide tab for her details and some tips on how to prepare for interviews.
You might not have heard of the STAR technique which can be used for competency based questions (Tell me about a time when you have, Give me an example of etc.).
If you remember this acronym, it will help you structure your answers and you can prepare some examples in advance.
Situation: What was the situation you were faced with?
Task: What did you have to do?
Action: How did you go about completing the task?
Result: What was the outcome?
Examples are given in this article: