A bad handshake &amp; poor grooming is the one-two punch for kiss of death. Well, that, and only be interested in yourself because there's no room there for conversation.

The item I'd add to this list: looking over your shoulder (different from shifty-eyed) to see who's more important in the room. At that point I'm always thinking, "Oh, dude (or dudette), that would be anyone but you."