Get a grip
Tennis players hold the racquet differently to hit different shots so why shouldn't you as a golfer? In the first photo below, I have used a marker pen to show the V formed between the thumb and index finger of the left hand that I will refer to during the rest of this instructional article. The second photo below shows a neutral grip where the Vs of each hand point roughly towards the right shoulder (for a right-handed golfer) whilst at address.
All things being equal, this should help the golfer hit the ball with a neutral ball flight. However, if you tend to slice the ball then why not experiment with a stronger* grip (photo 3) where the Vs point to the side of the right shoulder at address as illustrated. This would also help if you needed to deliberately hook the ball whilst on the course. Alternatively, to help combat a hook or if you want to deliberately slice the ball, try weakening* your grip as per photo 4. This involves turning the hands more anticlockwise on the grip so that the Vs point more towards the left shoulder at address.
Please experiment with these different hand positions and you'll learn a lot about how to control the clubface through impact which fundamentally is the key to good golf. Remember to hold the club more in your fingers rather than in the palms of your hands as this enables the wrists to naturally hinge more during the swing and consequently create more power without any additional effort.
* please note the terms strong and weak when applied to how a golfer grips the club are just golfing jargon. Effectively a strong grip produces more of a hook and hence a more powerful (i.e. stronger) ball flight. Conversely, a weaker grip produces more of a slice which won't go as far and hence this ball flight is considered weaker. So a strong or weak grip has nothing to do with how tightly a golfer holds the club.