Stand like you belong there. Posture is a sentence people read from across the room.

How you hold yourself gets read before anything you say, quickly and by everyone. Posture also affects the person carrying it, since standing as though you have a right to the space tends to change how the next few minutes go, partly because other people respond to it. None of that requires confidence you do not actually have.

Walk into the next room with your shoulders down and your head up, and hold it for the first minute. Treat it as a practical adjustment rather than a performance, and let it be awkward at first.