While some commands (like MOVE) automatically end after one action, others (like LINE) will keep going until you tell them to stop. There are four ways to exit these long-running commands: ESC, ENTER, space bar, or a quick right-click.
I've been sending these tips out to my office once a week for about three years now, and decided to start the blog as a way to put them all in one place. Who knows, maybe they'll help somebody else out there too!
Some of the tips are pretty basic, but hey, we all had to start somewhere.
Most of the tips apply to AutoCAD 2004 & up -- I'll try to note if it's only available in later versions, but no promises. And ALL the tips apply to AutoCAD LT.
As always, if you have a tip you'd like to see featured, send it on in!