At worst, you might think I’m a bit weird for caring so much about sound quality. Or you might think I’m really weird if you knew that my loudspeakers are computer calibrated to my room. Or you might question my priorities if you knew I set up my office, so that my desk is nearly in the middle of it… mainly to be able to enjoy music better. But we’re all weird in some ways (and I’ll let you think this is the weirdest thing about me).

Think about mobile. If a campaign doesn't show up on mobile devices, it's not going to perform very well. Everything you send should be mobile-friendly. Check out ReturnPath's "Email in Motion" infographic for some data that might affect the way you design your emails. One of the highlights: According to the study, 63 percent of Americans and 41 percent of Europeans would either close or delete an email that's not optimized for mobile. Might be time to start using a responsive template.
You might consider making the language in your alt text actionable, such as "Click here to download the ultimate content creation kit." Actionable alt text will essentially turn every linked image into another CTA. So, even if someone doesn't see the snazzy GIF of my latest offer (or if they hover their mouse over an image that does show up), the alt text will beckon them to click.
Even if you’ve already got a long list of emails for clients and prospects, you should never stop adding to it. Especially since it’s not nearly as hard as it sounds. For example, make sure your list is always growing passively with a signup feature on your website. Subscription forms should be on your home page, blog page and everywhere else you can fit it without taking away from more important content.
Use your real email signature: Just like using a real reply-to email address, you want to use real contact information within the email and the best way to do that is to include your contact details in the email signature. Giving your readers the opportunity to contact you or connect with you online is a great way to be personal and build a relationship with them.
When you're using email as a marketing tool, you're working on a pretty personal basis. This isn't ‘drive-by' stuff -you're directly targeting customers from their inboxes. There's a huge amount of potential which comes with this kind of marketing... but you'll only reap that potential if you REALLY understand both the marketplace you're operating from, and the audience you're talking to.