The shank is a golf shot that flies extremely low and to the right very dramatically but it is no different than any other shot in golf that you want to improve. There is a reason and cause for it and once you understand this you will be able to correct it and begin hitting much better golf shots.
The shank in golf is caused by having a backswing that is too flat. To explain what this means, place an alignment pole on the floor in front of you to represent the line you want to hit a straight shot along. With a second alignment pole, place this approximately three inches to the right of where the ball would be so that it is angled approximately 45 degrees towards you. If you have a flat backswing, you will make your initial movement away from the ball below this alignment pole, that’s what flat means - it means the club head is moving below the pole. This will result in swinging back towards the ball from under the pole, instead of swinging along the target line and with the club face open, that means aiming to the right of the target, and you will hit a shank.
To correct this, work on swinging away from the ball just over the pole and then swinging back towards the ball again from just over the pole. This will allow you to swing your club head straight along the line you want to hit the ball along and with the club face aiming along this line, the ball will fly straight. If you do not have any alignment poles you could use one of the following drills to help you with how to alter the movement you currently use. Put a stand bag, or your trolley and bag, in place of the alignment pole and swing the club head back just over these to get the feeling of how to hinge your wrist to allow the club head to rise above the bag rather than swing into it.
Similarly, you could stand with your back up against a wall. Take your set up position. If you are swinging flat, you will want to move the club head instantly into the wall. Learn to move the club head to the right of the ball, parallel to the wall so that the shaft of the club is in front of the wall, parallel to it at hip height.
Both of these drills will help you to improve your takeaway, or initial movement away from the ball and help you deliver the club head more appropriately back to the golf ball, swinging along the line that you want to hit along.