Don't admit to having produced poor work ever. Say you've probably made one or two mistakes - everyone does - but that you always do everything you can to put them straight, learn from them and made sure you'll not make the same mistake again.

Pick a relatively irrelevant skill and say that you don't find it as easy as you'd like, so you're working on it (don't just make this up - think about it and be truthful). Don't own up to a weakness in an area that's important to the role. As with the weaknesses question, you can state certain difficulties because they are actually quite acceptable, even commendable, they'd include: suffering fools gladly, giving up an impossible task, tolerating unkind behaviour like bullying, having to accept I can't help certain big problems in the world, etc. 

A great opportunity to shine and show management potential. Planning and organising is one of the keys to good work at any level so it's essential to acknowledge this.

Be honest.  Of course, everybody makes mistakes. But you always try not to commit mistakes, you always try to correct them and learn from the experience.

Absolutely I can - I get the guidance I need, and it may help prevent others from making the same mistake.

Prepare for this - be able to state your personal and career goals - keep them reasonable, achievable and balanced. Explain how you see the steps to reaching your aims. An important part of achieving progress is planning how to do it. Be able to demonstrate that you've thought and planned, but also show that you are flexible and adaptable, because it's impossible to predict the future - the important thing is to learn and develop, and take advantage of opportunities as they come along.