The email offers and call to action should be tested regularly. But it doesn’t stop there. Here’s a list of additional items to consider testing:
Which segments respond to your emails?
Which offer drives the greatest conversions?
What is the right balance of graphics and text?
Are you better served sending content with a lot of links or a single focus?
The list can go on to cover elements such as:
Length of copy
Intro text content
Intro text style
Body text content
Body text style
Closing text content
Closing text style
Bullets or numbering
View above the fold
Sense of urgency
Conversion—online, phone, or both
Refer a friend