Manipulate files:

1. C-x C-f Find a file (allows TAB completion)
2.  C-x C-s Save a copy of the current buffer to
     the corresponding file. If the buffer is not associated
     with a file, it'll prompt for a file name.
3. C-x s Save some buffers with the option of selectively
    saving them.

Manipulate buffers:

1. C-x C-b List all buffers
   (then C-x 1 to kill the window showing the list)
2. C-x b Prompts for the buffer to go to (allows tab completion)
3. C-x k Prompts for the buffer name to kill
4. C-x C-q Toggle read-only mode

Manipulate windows:

1. C-x 0 Delete current window
2. C-x 1 Delete all but the current window
3. C-x 2 Split the window vertically
    (with a horizontal line in the middle)
4. C-x 3 Split the window horizontally
   (with a vertical line in the middle)
5. C-x o Move to the other window
6. C-M-v Scroll the other window

Reference: A tutorial introduction to emacs.