My

:
Be yourself.
You rock, are articulate and kick ass every way till Sunday. That will show thru face to face. Unless this is the first interview the interviewer had ever done, they will see thru the BS and write you off as a fake if you try to be something you are not for the sake of trying to impress.
So far, I have yet to be fired
*knocks on wood* so I really don't know how to handle that part of the interview, but if it were me, I'd be honest. "I gave the job away, learned lessons X Y and Z, and won't do it again."
We're all rooting for you, and you know it. Kick ass!!
Oh, and if you don't get interviews right off the bat, don't fret too much (I know, easy for me to say, who's not eating ramen and saltines for dinner) a lot of places have to post jobs even though they already have someone internally that they planned on putting in that position. Keep at it, and post here to help let the steam and nervousness out.