For you veterans, I know you already know this, but this should be helpful for newbies
I routinely get double and triple the opens on every email that I write.
I know this works for Aweber, but I assume it also works for other major autoresponders as well
Here's what you do:
1. Send your regular email to your list
2. After a few hours (3-4) pull up the stats for the send and click on the "No Opens"
3. Save these "No Opens" as a subset from your list
4. Re-mail this new subset using a new subject line
5. Repeat steps 2-4 for second email
That's it ... Very quick to do and very effective.
It essentially gets more people reading your emails (2-3X's) and doesn't piss off the people that already opened the first email
Hope this helps