When the project goes well, push credit down. When it goes badly, take the hit at the top.

The two instincts run the other way by default. When something works there is a pull to stand nearest the result; when it fails there is a pull to find whose part went wrong. Reversing both is what makes people willing to try things around you, because the risk of being blamed is the main reason anybody plays safe.

Next group project, say a specific name out loud when the teacher is pleased, and say we when they are not. If something you organised goes wrong, say you organised it. Watch how much more people attempt the second time.