Every Emacs user knows what C-x o (other-window) does - it moves your cursor to the next window. When you’re out of windows - the command will take you back to the first one.

Relatively few people are aware that the command takes a prefix argument which allows you to move several windows forward or backward. That’s obviously pretty useful when you’re a heavy window user and like to split your frames into many windows.

To move 3 windows forward you’d do C-u 3 C-x o. To move 2 windows backwards you’d do C-u -2 C-x o.

If you’re mostly working with only two windows you probably don’t need to know that much about other-window - after all invoking the command one time will take you to the other window and invoking it a second time will take you back to the window you were originally in. I, however, often employ 3 or windows (blessed be the people who made huge LCD displays so cheap) and I really dislike having to type C-u -1 C-x o (or C-- C-x o, M--1 C-x o or M-- C-x o for that matter) to go back to the previous window. To alleviate that particular nuisance I utilize the following little trick:

(global-set-key (kbd "C-x O") (lambda ()
                                (interactive)
                                (other-window -1)))

Now pressing C-x O (that’s not a zero, it’s a capital o) will always take me to the previous window, no matter how many windows are currently present.

The C-x O keybinding is available out-of-the-box in Prelude.