Tips on designing scaling icons

Tips on designing scaling icons


I'm building an audio player with JQM and I'm now at the stage where I want to add pretty UI controls for the play button, skip button, etc. 

My question is, does anyone have any tips or guides on how to create responsive controls that scale to any size device, big or small? 

I have an idea that it will possibly require the creation of different sized icons with media queries applied in CSS to decide the most appropriate icon. However, I need a good starting point as to what sizes I would need and SVG/PNG fallback.