Give examples with real results - for instance, don't say "I'm really good at patient care", say, "when I worked at xxx I introduced some new methods of working which notably improved patient care in my area - my manager's thanked me for this and I showed other people what I did" so, not just what you did - but the impact it had, how you dealt with real situations - and the result. Sorry - but I don't ' know about NHS interviews, but I imagine they would want to learn what you could bring...