During
If you’re making a presentation, speak clearly and confidently. Look at your tutor and other students as much as possible, rather than just reading from your notes.
If you’re listening to a presentation, don’t interrupt people while they are speaking. During this time take notes in the same way you would in a lecture. They will signal when it’s time to ask questions or start the debate.
Once the debate starts, it’s very important to contribute. Sometimes you might be asked a direct question by a tutor, at others you will have to make a point yourself without being asked. It’s fine to disagree with what another person says, but be polite and give your opinion without sounding like you’re arguing.
Don’t worry if you don’t like speaking in public. You won’t look stupid because the whole point of seminars is to share ideas and find out what others think, so there aren’t any ‘right’ or ‘wrong’ answers.