Responsive Design with WordPress By Joe Casabona

http://www.mydesignshop.com/responsive-design-with-wordpress
Find out what to consider at the outset of the design process to save hours of work during redesigns. Learn up-to-date best practices for determining breakpoints, accessibility, and preventing website bloat for better user experience no matter the user's connection speed. Finally, you'll apply the principles you learn to specific tutorials, such as building a photo gallery, map page, and products page.