Practice in front of the mirror or video tape yourself. Call random stores or businesses and talk about an item or anything really but try to introduce yourself. It’s easier to see what you’re doing wrong when you watch yourself stuttering. If you’re anything like me, stuttering usually comes from tensing up and trying to force the word out. If you can say it normally when you’re alone then you need to practice saying it under pressure. There are tons of great stuttering self therapy books out there as well.