The golf swing is quite complicated. In short, if it is not balanced, smooth and powerful, a golfer will lose accuracy, distance and consistency. A slice is one of the most common problems that golfers face. With significant effort, a golfer can arrest the slice and build a proficient and effective golf swing.
If you are aimed incorrectly, the chances are that you will hit the ball off course and a slice will be the result. In an effort to get rid of a slice, many golfers open up their stance with the idea that they would rather pull their shot to the left than slice it to the right. That's the opposite of what happens. The incorrect placement of the feet at address actually pushes the club head to the right. Square your shoulder to the target and place your left foot directly underneath your left shoulder. That should give you a much better opportunity to hit a straight shot.
You need a firm grip when playing golf, but holding it too tight will restrict your body and cause an outside-in swing. Holding it too loosely, however, will cause the club head to wobble or move on contact. You want the club head to hit the ball squarely. You need a firm grip to accomplish this. Hold your club with a grip strength of "5" on a scale of 1 to 10. That should keep the club head in place on contact. If you still have issues, you may have a so-called "weak grip", caused by improper hand placement. Try rotating your hands clockwise to keep your thumbs off the top of the club.
Don't rush your swing and don't go too slow. Let your hips trigger your swing. If you want to hit a straight shot with good distance, turn your hips to the right to get started. After you get to the top of your swing, shift your weight to the left and make sure your hips follow. If you bring the club down and through the ball after your hips have cleared the hitting zone, you will get rid of your slice.