The number one thing to do is to make sure your email template is mobile responsive. If you are using a mail service like Mail Chimp, that work is done for you. But if you are using a CRM that requires you to create the template, you want to ensure it is designed for mobile. Gmail can be especially tricky with responsive. Here is a great tutorial that goes over designing for Gmail: http://webdesign.tutsplus.com/tutorials/creating-a-future-proof-responsive-email-without-media-queries--cms-23919. But if you don't have someone on staff that does your web/email design and you're technologically challenged...this is definitely something to invest some money in a good template for.

Second, for email copy, you want to keep it short and your calls to action, near the top of the email. Think about how you personally read email on your phone...having to scroll down through an email, after a few scrolls, you stop and move on. Make sure you get your point across early so that people don't move on past your key message. All graphic emails and short infographics also do well on mobile. I love this website for inspiration for short or graphic emails: http://reallygoodemails.com/

Third, take advantage of the preview text in your email. Preview text is the snippet of copy pulled in from the body of your email and typically displayed underneath the from name and subject line in a subscriber’s inbox. You want to grab people's attention here so that they open your email. Here is a great article on taking advantage of this text. https://litmus.com/blog/the-ultimate-guide-to-preview-text-support

The biggest pitfall most email marketing campaigns include is a focus on a newsletter-style template with photos, boxes, etc.

My email open rate jumped up when I started sending text-centric emails using ConvertKit. They're still technically HTML emails because they include hyperlinks (like you would send a link to a friend) but they're more personal, far more likely to make it through spam filters, and readers find them easier to read.

Beyond that, here are a few tips:

1. Write an engaging, personal headline
2. Draw readers in with the first sentence of your email (Gmail and other ESPs display this alongside the title)
3. Send at the same day and time each week (build consistency, expectations)
4. Ask questions often (replies boost delivery in Gmail)
5. Use mail-tester.com before you send every campaign

Hope that helps! If you want to get into more specifics, send me a message or schedule a clarity call.

I'm a Digital Marketer Certified Partner and they have some pretty valuable videos and material regarding e-mail marketing. You might want to look at some of what they offer, especially the 101 Best Email Subject Lines of 2015 for inspiration. Here's the direct link: http://www.digitalmarketer.com/101-best-email-subject-lines-2014/.

The one piece of advise I'd give to you, and anyone else, is to get that double opt in and make a big effort to teach your consumers how to whitelist / add your e-mails to their address book.

With Google it is helpful if they star and tag your e-mails. Google learns what you want in your primary inbox and what you don't by how the tool is used. Providing highly valuable content to your audience will help keep engagement up.

Hope that gives you some places to start.