Common methods of emphasis:

Not highlighting:
* italic text
* slanted text
* sans serif font
* monospace font
* small caps

Highligting:
* bold text
* underline
* text color
* background color
* bullets or other marks
* larger/smaller type
* letter spacing

Resources:
* Some information available from [wikipedia article about emphasis|http://en.wikipedia.org/wiki/Emphasis_%28typography%29].
* [Emphasis on Web Style Guide|http://www.webstyleguide.com/type/emphasis.html]