A habit many amateur golfers develops is the hips moving forward before the hands moving forward. This tends to create a slice because the clubface is left open at contact.
A good way to remedy this? Hit a lot of golf balls with your feet together. This will isolate the lower body a little, allowing your hands, arms and club to swing and release through the golf ball.
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If the hips get away from this posture, you will lose your balance. Second, hit balls dropping the right foot back behind the left foot. While doing this, swing to the right of your intended target. This will shut your hips and allow your hands to get down in front of your body.
This will force the club to release over, causing a right-to-left shape to the ball. This same drill, keeping both feet in the ground throughout the swing, will pronounce this effect. Another drill is to hit balls with one hand. The dominant hand will enhance the timing of the club with the lower body creating an in-to-out path. This forces the club to release through the ball. Good luck practicing!