Congratulations!
I've seen many different characters serve as team captains. Here are some principles I would consider important:
- Responsibility - take responsibility for tasks that you are assigned
- Communication - communicate, communicate, communicate. Make sure what was said is what was heard.
- Planning - a little planning goes a long way, even if you don't follow the plan
- Representation - as team captain, take concerns that the other students have and bring them up with the lead mentor
- Improvement - take the time to learn what your team does well and what it does not and offer suggestions to the lead mentor
- Fun - don't forget to have it!
Note: many teams are led by the lead mentor. You will have a set set of responsibilities, understand these and perform the duties you agreed to. You may or may not be responsible for running the team.