As I said, the grip does not have much to do with the swing plane of the club and so your swing plane may be perfect and yet you are still slicing it. The thing to note is that the direction the clubface is facing at impact can very much be influenced by your grip. The cause of your slice may be an open club face at impact and this could be caused by a poor grip. So, how can you ensure you have a proper grip to help you find out how to correct a golf slice.
Gripping a golf club can be done effectively but differently by different golfers. People find grips that work for them and the shape and size of their hands. However, when it comes to slicing, very distinct faults can be identified in someone's grip. Usually an open face at impact is caused by having either or both of the hands too much on the left side of the grip handle. So, in trying to find out how to correct a golf slice there are some simple checks you can do to check your grip is correct. First take a normal setup as if you are about to strike a shot and check how many knuckles you can see on your left hand. If you can see at least 2 then your grip is most likely not the reason for your slice. A similar check is to ensure the V shapes formed by both your hands on the grip both point towards your right shoulder.
Taking a solid, neutral grip is one of the first steps to hitting straight shots. If you're a slicer and your grip fails one of the checks then you should certainly take a closer look at how you grip the club.