Responsive Drupal Theming, Done the Right Way... At Least For Now Anyway
Mark Carver has written a post with a list of techniques on Drupal responsive theming:
A little over a year of following my own advice, I decided to re-visit the long overdue topic of responsive theming and share several valuable techniques and processes I've learned along the way.
He discusses the framework to use (Omega), CSS preprocessors, media query mixins, and the Display Suite module. Well-worth reading before your next responsive design project.