I practiced by talking to my phone and filming myself stuttering while alone, for 10 minutes at a time. I would just talk about my stutter and my day in general. It was super weird to hear my own voice, and I noticed that I could still stutter even when I was alone (I used to think I was perfectly fluent when speaking by myself). Eventually, after about 20 days and around 15 sessions, I started noticing some good gains in fluency. Another thing that has helped is sending voice messages whenever I can. At first, it took a lot of tries I would cancel and re-record them but now I can usually get it right on the first or second try.