Don't assume failures disqualify you. Most pilots (I'm guessing) have something on their application that needed to be 'discussed' during the interview, be it speeding tickets, checkride failures, GPA, etc.; call them 'red flags'.

The formula for any 'red flag' on your application is the same:
1. State the facts- ie. this is the maneuver I screwed up on. I was pulled over for XYZ. I was doing 68 in a 55 zone.
2. Take responsibility- I don't care if the examiner didn't like the way you dressed, or the police officer 'had it in for you', acknowledge and accept that you did something wrong. (not whether or not you deserved it)
3. Tell what you learned from the event- I should've been paying more attention to the speed limit signs. I needed to focus more on the moment and the maneuver instead of dwelling on that little mistake I made earlier in the ride.
4. Show that you applied that knowledge- You'll notice from my record that I haven't had a ticket in the last 10 years. As you can see in my training records, I haven't had any training issues since that event.

For anyone going back for a second interview somewhere, this formula can even be applied to interview failures. Treat them just like any other 'red flags'.