I might've told you this in another thread unless it was someone else, but this one will do.
Medal level goes down every single time you get hit, so rolling is the key despite the awkward position it puts your hand in since you have to hold X while rapidly moving and pressing O. (As much as I like the gummi ship and have become all knowing in the subject, it would be TWICE as good if those jackasses made square the roll button instead of circle)
And because you can't equip the draw ability to your ship at this point, you have to fly into the medal orbs as the enemies drop them.
As long as you avoid being hit, it is easilly possible since I can get max medal level of 30 with a low level, slightly modified falcon ship.