What resolution am I running?

xdpyinfo | grep dimensions
xwininfo -root

Do I have hardware video acceleration in X?

glxinfo
xvinfo

Check X errors in

~/.xsession-errors

Checking terminal column and width environment

resize

Checking if DPMS is enabled et al

xset -display :0.0 -q

How should I set my resolution?

randr -s 1680x1050

How do I configure Xorg?

Place settings in /etc/X11/Xsession.d

x61:~% cat /etc/X11/Xsession.d/55xvideomode
xrandr -s 1024x768