Don't use CTAs to drive people to your homepage, for instance. Even if your CTA is about your brand or product (and perhaps not an offer like a download), you should still be sending them to a targeted landing page that's relevant to what they are looking for and includes an opt-in form. If you have the opportunity to use a CTA, send them to a page that will convert them into a lead.
Marketing emails need to be personalized to the reader and filled with interesting graphics. Few people want to read emails that are addressed "Dear Sir/Madam" -- as opposed to their first or last name -- and even fewer people want to read an email that simply gives them a wall of text. Visuals help your recipients quickly understand what the point of the email is.
Not only is InVision's newsletter a great mix of content, but I also love the nice balance between images and text, making it really easy to read and mobile-friendly -- which is especially important, because its newsletters are so long. (Below is just an excerpt, but you can read through the full email here.) We like the clever copy on the call-to-action (CTA) buttons, too.
Clearly, there has been a huge change in the traditional buying process. In fact, according to Forrester, buyers might be anywhere from two-thirds to 90% of the way through their buying journey before they even reach the vendor. The reason this is happening more and more is because buyers have so much access to information that they can delay talking to sales until they are experts themselves.