What would be 3 good subpoints for this mainpoint National Championship Records/Bowl Records?
What is your thesis statement?
The History of the SEC conference in football/most dominant conference.
That's not even a sentence, much less a thesis statement.
Study this and decide on a thesis statement.
http://leo.stcloudstate.edu/acadwrite/thesistatement.html
The SEC conference is the most dominant conference in football.
Good.
Why do you think that it's the most dominant conference? What are three reasons for its dominance?
Those three reasons will be the three subpoints.