1. Move rear hip without turning shoulders, collapsing back knee (keep over toes) or moving front hip (though move slightly down and forwards with the front knee).
2. Keep the elbow in line with the hip and mentally connect to it. Don't move the arm until it connects with the target. Don't let the elbow flare out sideways.
3. Try not to think about hitting the opponent as this directs your energy into the shoulder, arm and hand when it should be in your hips and feet.
Simple!