Tell the interviewer about something (real or fictitious) which used to be a failing but which you've worked hard to overcome.
e.g: "I know that, in the past, I've been rather poor at delegating responsibility. I suppose that's because I've wanted to ensure that everything has been done to the same high standards which I've always set myself. I've come to realise, however, that it's important to show trust in my colleague's abilities, so I hope that I'm much better at delegating responsibility than I used to be."
That's a rough version of what I used the last time I was asked the question - and I got the job! It won't help much, however, if the job you're after doesn't involve delegating responsibility. In this case, try turning it around to something like this:
"Well, I used to be rather hesitant about asking questions but I think that my self-confidence has improved and I don't think that I'd have any problems seeking advice if I worked here".
Note that both those statements provide an opportunity for pointing out positive qualities. The first one says "I always demand high standards from myself and others". The second one says "I'm now a self-confident person with a willingness to seek out information to help me do my job well".
Hoping this helps,
Chris