[catamount]

In addition to sheeting angles for the headsail, the ability to maintain or adjust tension on the headstay is also important, typically done with some sort of adjuster on the backstay -- i.e. tightening the backstay will in turn tighten the headstay, reducing wind-induced sag and maintaining sail shape and pointing ability.

Generating hydrodynamic lift from the keel is also really really important. Deeper fin keels with appropriate foil shape are best. If the boat stalls, you want to fall off to get flow going over the keel to start generating that lift.

Obviously righting moment will be important, too -- thus the heavy bulbs on the ends of long keels, and the row of heavy people hanging by their butt cheeks from the weather rail. Generally, the more upright the sails are, the more effective they are at moving the boat forward rather than sideways.