Do you have a good idea? Voice it.

Do you have something burning on your chest? Say it.

Is there a statement that you don't agree with? Share your opinion.

Do you have a question? Ask. The general rule of thumb is that we shouldn't worry if we ask stupid questions, so don't be shy. You've probably got the same burning question as some of your colleagues.

Let your voice be heard at meetings. If you don't speak up, there's a good chance someone else will. I once had a boss who said that if people don't contribute in meetings, there's no reason for them to be there. I agree with that statement.