In the descriptions below, C stands for the Ctrl key and M stands for the Alt (Meta) key. When you see a key combination like C-g you should hold down the Ctrl key while pressing the g key. When you see a key combination like M-f you should hold down the Alt key while pressing the f key. (Note: for M-key combinations, you can also tap the Esc key and then hit the second key (i.e., don't hold down the Esc key)).
C-x C-c Save buffer to file and exit emacs C-x C-s Save buffer to file and remain in emacs C-x C-f Open a file in a new buffer C-g Cancel command C-x u Undo
C-f (C-b) Forward (backward) one character M-f (M-b) Forward (backward) one word C-n (C-p) Next (previous) line C-a (C-e) Beginning (end) of line C-v (M-v) Page down (up) M-< (M->) Beginning (end) of buffer C-l Redraw the screen centered at current line
C-s (C-r) Search forwards (backwards) M-% Search and replace M-g g Go to line number
C-Space Set mark for beginning of region to cut or paste C-w Cut from first mark to current cursor location M-w Copy from first mark to current cursor location C-y Yank back the cut or copied region to the current location C-d Delete character M-d Delete word C-k Kill line