Easy: don't speak authoritatively. Acknowledge the limits of your knowledge and invite better information from people who know better.

I would advise not speaking authoritatively even if you are an authority. People are less likely to offer suggestions and ideas you didn't consider if you act like you know what you're talking about. I learn all kinds of things by not sounding as certain as I usually am.

...they said, authoritatively. I'm a work in progress.