Use Formatting to Guide Your Reader
The formatting in promotional copy should guide the prospect through your letter to the sale.
Set subheads in a bold font that’s different from your body copy. Body copy should be an easy-to-read serif font like Times, so make subheads an easy-to-read sans serif font like Helvetica.
Quotes (such as testimonials) are most effective set in italics and indented from both the left and right margins. This sets them apart from the body copy and gives them importance.
Warning: Beware of long stretches of italics. It’s harder to read … and you want everything about your promotion to be easy to read.
Use underlining or boldface for emphasis – but (usually) not both at the same time. Like a good spice, too much overwhelms the senses.
Emphasized text should jump off the page and grab the prospect’s attention. If it’s overdone, the page jumps around visually, looks unfriendly, and is hard to read.
You might think it’s up to the designer to make formatting decisions like these. But YOU are the expert on convincing the prospect to buy, so your copy should have these subtle signposts before it ever gets to designer.