Some Gnome 3 Hints
General Tips
Many Gnome3 changed settings apply immediatly. For those claiming to require a restart or logout+login, usually restarting the shell is satisfying: Alt-F2, r, Enter. This also seems to make some software updates count faster.
Some of the tips may apply to only Gnome 3.0 and 3.2, be aware of the switch from gconf to gsettings (or whatever).
HowTo ...
How to switch modal dialogs from attached to decorated+movable (gconf-editor, /desktop/gnome/shell/windows, attach_modal_dialogs)
How to include the 2nd monitor in workspace switching (gconf-editor, /desktop/gnome/shell/windows, workspaces_only_on_primary)
How to reduce the time after which Alt-Tab shows the window list (watch out for the comment about POPUP_DELAY_TIMEOUT in /usr/share/gnome-shell/js/ui/altTab.js)
To give workspaces names: gconf-editor, /apps/metacity/worspace_names, name_1, name_2, ...
Install Gnome Extensions (System Monitor, etc.)
Restart the gnome shell without logging out: Alt+F2; r