I've had the pleasure of sitting in on auditions the last few days. And I've learned something very important. It's applicable to any presentation, not just acting:
When going in front of a group of people, make sure that you don't have anything hanging out of your nose. Especially when your nose is fairly large. Or if you're a "close talker".
There's really no excuse for not checking yourself out in the mirror before trying to land an important job. I mean, this person had to have blown their nose recently, right? That's the only excuse for...
I can't go on. It's too gross.