Being the most informed person in the room beats being the loudest person in the room almost every time.

Volume wins the first two minutes and knowledge wins the hour. Loudness is easy to produce and easy to discount, while specifics tend to settle a question, because a fact somebody actually checked leaves little to argue with. Information lasts, too: the loud contribution is forgotten by Friday and the useful one gets you asked again. Preparation is the quieter form of confidence.

Spend twenty minutes finding out before the next meeting, class discussion or family argument that matters. Read the thing, check the number, ask the person who knows. Then say less than everybody else.