I personally surround the text in a box to offset it from the surrounding text.
I posted a sample EPUB in Post #5 and linked to an example of a variation (gray box) in Post #10:
https://www.mobileread.com/forums/sho...d.php?t=218023
You can see sample images of it in action as well. I think it works quite well.
There are also a few more examples given in that topic.