Same as a regular one, you just hand pour over a single cube of ice and toss in an olive, onion, lemon, whatever. Stir with your finger and go. No straining, no stir stick, no measuring, one cube of ice.
I've learned that I don't give a shit if a martini is shaken OR stirred. They're all fucking disgusting. I love gin, but who the fuck thought super salty gin would taste good? The olive is the only good part of the whole thing.