I’ve tried so many things throughout my life. Getting yourself to stop is going to be a personal thing. The last thing I tried that succeeded was taking a job out of town where I worked 12-16 hour days. It was manual skilled labor. I was working with my hands, they were often dirty, and frankly, there wasn’t much downtime to find myself chewing my nails. This attempt to stop just happened to finally work for me. It’s been almost four years. Keep at it, you can do it!