Keyboad shortcuts

Ctrl-H: show hidden files
Ctrl-N: new window
Ctrl-Shift-N: create new folder
Alt-Home : jump to home folder
Alt-Enter : file / folder properties
Alt-F1 : launch application menu
Alt-F2 : launch "run application" dialogue
Ctrl-Alt - Right/Left arrow : move to the next virtual desktop
Ctrl-Alt-Shift - Right/Left arrow : take current window to the next virtual desktop
Ctrl-Alt-D: minimize all windows, and gives focus to the Desktop
Alt-Tab: switch between windows. When you use these shortcut keys, a list of windows that you can select is displayed. Release the keys to select a window.
Ctrl-Alt-Tab: switch the focus between the panels and the desktop. When you use these shortcut keys, a list of items that you can select is displayed. Release the keys to select an item.
CTRL + ALT + Enter: for toggling Full screen mode in rdesktop
ALT+ENTER: Show file properties without right-clicking the mouse



2.How to create a custom hotkey to launch whatever application you want in GNOME:
As an example, we will set a lock-screen shortcut.
Open "gconf-editor" as the user as you're logged in in GNOME (typing gconf-editor in the terminal or "Run Application").
Go to apps > metacity > keybinding_commands
Here we have a list of twelve slots for commands. Double click on e.g. "run_command_1"
In Key Value Type in the name of the application or command you want to launch (e.g. gnome-screensaver-command --lock).
Go to apps > metacity > global_keybindings
Double click on e.g. "run_command_1"
Change the key value to whatever key combination you like (e.g. L).Press "Ok".


3.How to create/change GNOME shortcuts:

Click on System > Preferences > Keyboard Shortcuts
Click the action in the list and press Enter.
Press the new key or key combination you want to assign to the action. (To clear a shortcut, press the Backspace key)

References:
http://www.linuxquestions.org/questions/linux-newbie-8/most-used-shortcuts-in-gnome-and-nautilus-640504/