Some preliminary tips for shido-geiko:

(i) Join-in the practice

Do not stand and watch. Your role is not to observe.
You need the practice as much as the other students do.

Participate, and explain what you are doing.

(ii) Try to work with all group members

Do not play favourites, regardless of whether you like someone or not.
If a student is willing to train with you, they deserve your respect.

(iii) Speak loudly and clearly

This may require some confidence, but you cannot express energy if you are quiet.

(iv) Disciplinary measures

If someone is difficult with you, speak to your instructor about them.

Your instructor will not discipline people who are not getting the material.
Disciplinary measures address attitude, not competence.

(v) Do not discipline people yourself

Disciplining people is a tricky skill and is best left to the instructor.