You've received great thoughts already. I'll just add a few links to the Davidson Database as a roundup of resources for helping a child develop self-advocacy skills (some of which may be helpful for a student-led conference):

1) Self-advocacy for gifted teens and tweens: How to help gifted teens take control of their classroom experience
Archived on WayBack Machine -
https://web.archive.org/web/20160507035437/http://www.davidsongifted.org/db/Articles_id_10849.aspx

2) Self-advocacy: The Power of Speaking Up
Archived on the WayBack Machine -
https://web.archive.org/web/20170919025332/http://www.mtagate.org/uploads/1/1/7/4/11741428/fisher_selfadvocacy.pdf

3) Davidson Discussions (youtube video), Self Advocacy

4) Four Simple Steps to Self-Advocacy
Archived on WayBack Machine -
https://web.archive.org/web/20160413004205/http://www.davidsongifted.org/db/Articles_id_10458.aspx

5) Other Resources listed on the Davidson Database
Archived on WayBack Machine -
https://web.archive.org/web/20150321123707/http://www.davidsongifted.org/db/Articles_id_10761.aspx

6) Blog post July 2017, for parents
Archived on WayBack Machine -
https://web.archive.org/web/20171005170716/https://freespiritpublishingblog.com/2017/07/20/empower-gifted-learners-to-advocate-for-themselves/

7) Blog post Sept 2017, for teachers
Archived on WayBack Machine -
https://web.archive.org/web/20180224153324/https://freespiritpublishingblog.com/2017/09/19/3-things-gifted-students-wish-their-teachers-knew/

8) New Book, Oct 2017 - The Power of Self-Advocacy for Gifted Learners, Teaching the 4 Essential Steps to Success
Archived on WayBack Machine -
https://web.archive.org/web/20171005170718/https://www.freespirit.com/teaching-strategies-and-professional-development/power-of-self-advocacy-for-gifted-learners-deb-douglas