As a marketer, the chances are good that you're receiving emails from several other lists. Do you notice that you open some marketers' emails more than others? You can learn a lot from this.
Save the emails that really grab your attention and make you respond, either by “labeling” them if you're using Gmail or sorting those messages into a folder marked “swipe”. Better yet, set up Evernote and Gmail so that when you tag something with “swipe” it gets sent to Evernote (use IFTTT).
You can “swipe” certain copy ideas (not the subject lines themselves, but the ideas used) for use in your own emails to make them more attention-grabbing and response-inducing.
You should do this with every bit of email that gets you to take action.