The XFCE wiki has a FAQ, "Tips and Tricks" and other useful stuff:
XFCE is most definitely suitable for beginners. I learned much of what I know about XFCE just from playing around in the XFCE 4 Settings Manager. XFCE strikes a good balance between the more full featured desktop environments like Gnome and KDE, and the more frugal austerity of window managers like Fluxbox and Open Box.
Robby Workman has lots of XFCE plugins and packages (32 bit and 64 bit versions) on his site: http://rlworkman.net/pkgs/
Most, if not all of these are available at http://slackbuilds.org/
also. You can read up on available XFCE plugins and packages at the XFCE goodies site: http://goodies.xfce.org/