This is for a basic 2 monitor setup within 2 minutes.
- Plug in both monitors
- do xrandr, it will tell you the names and available "modes" (resolutions) for both
- issue a xrandr command with the appropriate details, for example
xrandr --output HDMI1 --mode --noprimary --right-of DP1
- after this, restart Qtile (default win+shift+r)
And you'll have multimonitor, and its pretty good already (the interface is diff from dwm, but I kinda like it, basically think of it as having 10 workspaces, and being able to see any of them on any monitor). No need for config.py hacking or xorg.conf etc.
Hope this saves somebody an hour or two.