Move with Purpose (or The Removal of Unnecessary Motion)
One of my personal favorite shorthand directions when working on a staged play I stole from my second ex-wife.
"Move with purpose."
So simple.
Translated it means that if you are going to cross from point A to point B, have a reason to do so that connects with the character's life in the play. It funnels down to mean that all movement, down to scratching your face or tying your shoe needs to connect with your purpose. As an actor, it's an extremely helpful tool as I have a tendency to move around a lot with no function other than I just have lots of freakin' energy.
How do you want to be defined? By one action? By some opinion that could evolve? By a mistake, regrettable only with hindsight? Or by the sum of your parts? Okay, do that for other people. Start the trend.