Well... my best guess would be to go somewhere that the people won't know you and practice. Don't do anything you know is stupid, the goal is to learn. So just try talking to people, and if you don't get along with people you probably won't see them ever again. It's possible that you will, of course, but it's also possible that you will be murdered by a ghost clown next week. Just have to deal with it. The point is, you can throw caution to the wind and screw up as much as you need with little or no consequence.
That said, don't hang around in one place bugging people for hours. They'll think your loitering or trying to sell something... you never know what people will think of.
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When I allow it to be
There's no control over me
I have my fears
But they do not have me