Great piece. Some other tricks I’ve picked up:

1. Whenever I email someone for the first time, I’ll often then tweet at them right afterward explaining I’m a journalist and that I just sent them an email. That way they’re on the lookout for the email and will inform you if they didn’t get it.
2. Download a Gmail plugin that can track whether someone has opened your email. They’re not 100% accurate, but if a person hasn’t opened my email for several days after I sent it, chances are they either missed it or it went into their spam folder, and I know to follow up on another medium.