Mailing campaigns should be prepared in HTML format, preferably by the agency of the client. Here are some rules and good practices for preparing a successful campaign:
The campaigns are working better if they have a special offer for that specific occasion.
Always have a "call to action" button or buttons which says "Download the presentation", "Learn more", "Leave your contacts", "Arrange a meeting" etc.
The relevant part of the message should be always on top, and the campaign should contains images and a few sentences. Long text is not recommended.
Images must have alternative text.
The HTML should be 500 to 600 pixels wide. Recommended high is up to 1 000 pixels. This allows the message to be read with all kind of clients and devices.
Tables should be used for structuring the design of the HTML.
No active code (Java or similar) is allowed by email operators.