Add/Edit GDM Sessions
Each session is a *.desktop file located at /usr/share/xsessions.
You can change background image, gtk/icon theme by hands (as described at Gnome_2.28_Changes#Configuring_gdm_2.28), or you can use gdm2setup from the AUR.
If your gnome applications seem sluggish and gnome hangs at start-up after killing the previous session, it’s likely you haven’t set your /etc/hosts file correctly and your /etc/hosts file includes:
127.0.0.1 localhost.localdomain localhost YOURHOSTNAME
Then run “/bin/hostname YOURHOSTNAME” and “/sbin/ifconfig lo up” as root.
Due to an improper coded GNOME drawing library, some actions in GNOME can slow the system. If the theme icons are in SVG format, they make the system slower. A very fast improvement is to either use icons in PNG format or to convert the used icons into the PNG format.
Enable Volume Control as tray notification
Some users will have noticed that there is no volume control by default. It either can be added as a object to the panel or as a notification icon in the systray. To do the last one you have to replace gnome-media with gnome-media-pulse. This will install the volume control manager developed by Redhat and used in Distributions such as Ubuntu or Fedora.
# pacman -S gnome-media-pulse
Fonts Seem Skewed
You can alter the DPI of your fonts in Gnome with right-click on the desktop ? Change desktop background ? Fonts ? Details ? Resolution
Resolution:  dots per inch
Enable smooth Fonts
To have a nice and readable font configuration all you have to do is to click again with right-click on the desktop ? Fonts ? Details. Here you can set Subpixel (LCD) for Antialiasing and a low Hinting to have a optimal configuration. To be able to set LCD see the chapter on [LCD Font Configuration].
Change the Default Background Image
The default background is that zoomed in picture of a green leaf. It appears for newly created users, but more importantly, this is the image shown when the screen is locked. As of 25-Apr-2009, you can find this image here
To change it, simply copy your favorite image to this location (as root) and rename it.
Change the Default Background Color, Opacity, etc.
The default background color is green. You might want to change it if you’re using a transparent PNG as background.
$ sudo gconf-editor
Go to File ? New Defaults Window and edit the keys
You can also find keys for opacity, shading style, etc.
For more such tips head over to L: