Since journalists get so many emails, would it make sense to try to reach them via alternative methods right after sending the email. Maybe via Twitter, Facebook, calling them if a number is available, etc.
Calling would likely be too intrusive, so maybe just online ways of reaching them.
How much time would you say is idea until you should email them again to follow up (and they haven't responded yet)?
Good question Jordan.
I believe it depends on the nature of request or action you want to get from it.
If it's a pitch, I wouldn't be so overly aggressive. I'll give them like even 3 to 4 weeks to respond before I will decide to email them again.
If it's an urgent request (like news, etc), it would definitely be just days after.
With regard to social media like Twitter, I would just use it to support the email. So it would be something like:
"Hey Jordan, just a heads up. I sent you an email a few days ago. I hope you find time to go over it. Looking forward to your response."