Torqueing the bow happens when a twisting force is applied to the grip, or if unequal pressure is applied to the grip. For example, the way I usually torque the bow is to press on the grip with my thumb, which causes me to miss left. As Arne said, it is easier to feel a torqueing force if we hold the bow loosely rather than grip it tightly. Some longbow shooters really grip the bow and shoot very well, but evidently they can do it without exerting any twisting or unequal forces on the grip. If you take the conventional wisdom and grip loosely, just don't grip so loosely that you reflexively clinch your grip at the moment of release, or you will be introducing a new error. I hold the bow primarily with my thumb and index finger, with the other fingers just along for the ride, resting on the back of the grip. Since the pressure point on my hand is the meaty area below my thumb and to the thumb side of my lifeline, my knuckles angle away from the grip. There are variations to this you can try in blank bale practice until you come up with something that works for you.
Torqueing the string results in about the same symptoms as torqueing the bow, so you have to be aware of both. If you open your fingers and thumb at full draw so the bow is just resting in the V between your thumb and forefinger, and the bow wants to rotate to another position, usually to a more upright position, that means you are torqueing the string. The answer to that problem is to relax the string hand and forearm so the string hand follows whatever cant you put on the bow.