Many slicers hit the ball to the right simply because they are lined up to the right, when they go to hit the ball their mind knows the target is to the left and then subconsciously changes the swing to outside in so that the club travels towards the target causing a slice
This one, two, three Rhythm Drill is great for perfecting your tempo, just even out the timing, and allow your swing to flow with the count
Releasing your hands to late will lower the loft on the club and result in low shots