Your weight should be balanced on the balls of your feet. Feel relaxed but dynamically ready to start your swing.
Feet, knees, hips and eyes are parallel to the target line, with shoulders slightly open. Imagine a vertical line running through the right shoulder down into the balls of your feet. Lower back flat, upper back and shoulders rounded.
Your stance should be wide enough to promote stability and narrow enough to promote good motion. I like to see the stance just a little wider than shoulder width, but a touch wider with a driver.