I'm working on one of my first responsive websites and I'm trying to figure out for what kind of resolutions to optimize for.
Is there any standard or what? What are your practices? It would be nice to know.
Instead of designing "for screens", I would challenge you to use this method:
Design breakpoints around your content, rather than fitting your content to screen sizes (which change all the time). Start small, what's the best way to access my content on a small screen? Once you have that to start with, widen your browser. At what point does it become useful to revise the layout? There's your first break point.