For me personally that's a tough one. I've always been about 90-98 percent fluent (as in nearly no stuttering) when I'm alone and talking to myself. When I'm in an in-person conversation it's like there's this tiny, invisible, hair-trigger switch that gets flipped and all of the sudden my stutter is back to some degree. Right now I'm at the point in my speech therapy where I'm trying to get control over that switch. I think it's closely associated with a form of social anxiety/"headgames" that I just need to get through. Putting myself out there socially, as in not avoiding conversations or social interactions, is a low-key painful but necessary and effective way for me to get better at speaking. For you, I'd suggest focusing on what you're feeling as you enter a conversation and start feeling your speech becoming more difficult. Is it nerves or stress, or is it something else? Find out for yourself and go from there! And good luck! If it was easy then r/stutter wouldn't even exist and we'd all talk just fine. Keep at it!