Simulating Retina resolutions on a non-Retina Mac
If like me you have a non-Retina Mac you may want to fake a Retina resolution in order to get a larger working area.
I was searching for a simple way to achieve this for a while. Finally I found an app called RDM (Retina DisplayMenu). It simply adds an icon to the menu bar which allows you to go beyond the default resolutions. You can download RDM here (direct link).
Since this is faking it and you're still limited by the physical number of pixels you should not expect absolute clarity so it clearly isn't a good solution for playing movies or games. For development and general browsing however it is quite a handy technique. I found that on my 13" MacBook Air 1920x1200 works quite well which is a pretty nice improvement over the native 1440x900.