The biggest difficulty in curling is throwing a stone at a target applying a rotation movement to that stone while it leaves your hand. Curling wise, the throw primarily is a translation movement and at the most crucial time of the throw, when the rock leaves your hand, you must add a rotation movement to that stone without deviating from the translation (throwing line). It is very difficult to apply a rotation movement to a body in motion without deviating from its direction; unless the body in motion is maintain on its direction by rails or by any other means. In curling, the body in motion is a stone sliding on ice without anything to prevent the stone from deviating from its direction.
Techniques on release have been developed to face that difficulty. All the techniques start with a good grip and rock positioning: 10 O'clock for an "in turn" for a right hander etc… The thrower maintains the grip and the rock position both during the swing and the slide. He than apply the rotation to the stone on the last three feet (one meter) of the throw bringing the stone handle at noon. If the turn is applied during three feet with a good grip and a good rock position, the rock will do 2 ½ to 3 rotations on a draw. If the stone makes more than 2 rotations, we consider the release as being positive. A positive release allows the stone to travel straighter at the beginning of its slide to start curling later on facilitating throws control.
Here is my approach for a better release: As traditionally: Start with a good grip, high wrist Good rock positioning: 10 O'clock or 2 O'clock Maintain the grip and rock positioning during the swing and the slide. And, when you are ready to make the release, rather than applying rotation while releasing the stone,
TURN FIRMLY THE HANDLE UP TO NOON WHILE MAINTAINING THE GRIP ON THE HANDLE AND WHEN THE ROTATION IS COMPLETED (handle at noon) open the hand to release the rock at the target. (To know if the rotation is applied firmly enough, count the number of rotations on draws. You should get 2 ½ to 3 rotations).
My proposal consists in a two step release. First, apply the rotation and second release the stone. You think to turn the handle and only after you release the stone aiming at the target. During the second step of the release, no question of applying turns to the stone; the stone is already rotating. You simply have to focus on releasing at the broom.
The release is than completed by a translation movement which cope with the translation movement of the stone in curling.