Hi,
You have many great tips here already, I will also add mine to the list
1. The most important thing regardless of anything else is answering the question. Make sure that any example you give has the two elements mentioned here namely (a) It is a difficult challenge and (b) it clearly shows you leading the team through the challenge mentioned
2. Always prepare for these questions beforehand - practice is what makes the best answers
3. Make sure you communicate this in a structured way - I prefer the situation, complication and resolution framework because as a listener it is closest to a story format (begining, middle and an end)
4. Be enthusiastic and interested in your own story - you want the person listening to be engaged and interested in what you have to say. People react best to others who are interested in what they have to say
5. Use a style of speaking that is clear and easy to follow - I like using numbered points so people can tell where you are at any point
6. Be prepared for detailed follow-ups
All the best,
Udayan