I used to have a slice. Got rid of it. It is all about the swing loop. Take the club straight back but, then allow it to loop inside of that line and come from inside out on downswing. Also; rotate right hand from over the grip to behind the grip, so your right palm is facing the target.
Believe it or not; I was a Pro Bowler Silver Team USA coach level before I went blind. I figured this out after going to Pro school where Female Bowling Legend Carrol Norman helped me correct my arm swing. And; Then there is the breathing. Breathing is the most important part of promoting consistency. Just like Sharp shooters; It is all about the breathing and heartbeat. You snipers know what I mean