Take your icon game to the next level. Check out Fonticons, from the maker of Font Awesome.
             

fa-thumbs-down · Unicode: f165 · Created: v3.2 · Categories: Web Application Icons

After you get up and running, you can place Font Awesome icons just about anywhere with the <i> tag:

fa-thumbs-down
<i class="fa fa-thumbs-down"></i>

Looking for more? Check out the examples.