I used to edit a magazine. The layout, design, images and copy are there to encourage the person to read the article and become lost in it. It means, hopefully, that they will come back for more. The problem is that editors and graphic designers look at the page from their specific skills point of view: is the balance right, what about the colours, there are no rivers in the copy. There is a need for the objective view.
A method for doing so, which, whenever an editor discovers it for themselves, they become all but evangelical and suggest it to others, is one that takes a bit of nerve. Close the doors, pull your latest design up onto your VDU, and try, out loud, to describe to the imaginary person sitting on the other side of your desk the nature of the page in such a way they can replicate it. Tell them what makes the images fit in, what the point of the copy is, how the layout works, where the click throughs are; this for every feature.
For the images, say how it relates to the copy, and other images, how the eye follows them. For the copy, mention the layout, the hooks, the progressive build up. How does it run. Click-throughs are more than just above the fold, are they next to the hook of the email, or below the most important image? Does the heading relate to the product?
It works in reverse. When you find a remarkable marketing email from a rival, or any, company, by describing it verbally it will show what their trick was and, the point of the exercise, show you how to improve your efforts in your next campaign. If their ways impress, make them yours.
Don’t talk to yourself when HR are out and about.