Practicing your golf swing is something almost every amateur golfer does on a daily basis. Whether it is infront of the bathroom mirror or on the train to work, practicing different things in your swing is somehing that can really improve your overall practice. 

PGA professional Ryan Metcalfe agrees with this, and uses a simple back garden drill to help any golfer stop shanking or slicing the golf ball. 

The shank or slice typically comes from swinging "over-the-top," where the hands get above the correct swing plane and force the club path left(for a right hander) causing the ball to be hit off the hossle or with an open club face. 

By practicing your swing up against your garden fence, Metcalfe believes that it will consciously stop you from getting on top of the ball, as by doing this you will hit the fence with the club just like a slice or shank. Swinging underneath the fence will create a better and more positive club path, leading to better shot success.