With the knife handed strike, you are bringing the stick up to your same-sided ear and winding up your body at the same time. The movement comes from the hips, so be sure to wind the hips up in preparation for the strike.
As the strike is launched forward, you want the wrist and forearm to start twisting in towards the center of your body.
The strike is completed with a palm up position and with the stick in a horizontal position. Picture yourself cutting through the target.