How do I Change DPI for X Windows?

The DPI can be set when starting X windows. Changing the DPI can give you a bit more screen real-estate.

pi@raspberrypi ~ $ sudo FRAMEBUFFER=/dev/fb1 startx — -dpi 60

To make a permanent change;
edit /usr/bin/startx as root and enter in some default server arguments.

defaultserverargs=”-dpi 60”
serverargs=”-dpi 60”