Here’s a tip for you iPhone users: if you want to quickly open your last email draft in iOS, just hold down the compose email button for a few seconds. Your last email draft will open up right away. Nice.
For those who need things spelled out:
Save an email as draft
Hold down on the compose e-mail button in the left hand corner of the iOS mail app (as illustrated above)
Continue writing email
The email trick should work for you unless you’ve restarted your phone or closed the mail app. [Obama Pacman]