Ctrl + g - cancels current command
Ctrl + x u - undo
Ctrl + x k - kill buffer
Ctrl + x s - save all buffers
M-x - execute command
C-x C-f - open file
C-x C-s - save file
C-x C-w - save file as
C-x b - switch buffer
C-x C-b - list buffers
C-x k - kill buffer
C-s - search forward
C-r - search backward
C-g - cancel search
C-w - cut (kill)
M-w - copy
C-y - paste (yank)
C-x + - increase font size
C-x - - decrease font size
C-x 0 - close current window
C-x 1 - close all other windows
C-x 2 - split window horizontally
C-x 3 - split window vertically
C-x o - move cursor to other window
C-x 4 f - open file in new window
C-x 4 b - switch buffer in new window
M-x customize-themes - customize color theme
M-x customize-group - customize options for a group
M-x describe-function - view documentation for a function
C-h f - view documentation for a function
C-h k - view documentation for a keybinding
C-h v - view documentation for a variable
C-h i - open emacs manual
C-h t - open emacs tutorial