My first step is to remove the style.css content leaving the theme registration.
/* Theme Name: mrtwebdesign Theme URI: http://underscores.me/ Author: Matthew Taylor Author URI: http://mrtwebdesign.com Description: My own theme.. for me. Version: 1.0 License: GNU General Public License License URI: license.txt Tags: This theme, like WordPress, is licensed under the GPL. Use it to make something cool, have fun, and share what you've learned with others. mrtwebdesign is based on Underscores http://underscores.me/, (C) 2012-2013 Automattic, Inc. */
Not very exciting. But I’ll be using this file for CSS overrides if needed. I’ll generally just try to customize the Foundation files in place.