Depends of the game... In the minish Cap, The Great Spin Attack is the final sword technique learned
In twilight princess, The Great Spin Attack is the final technique Link can learn from the Hero's Shade. To perform the attack you need to have all hearts filled.
In Phantom Hourglass, The Great Spin Attack can be learned by completing a small trading quest near the end of the game.
In Spirit Tracks, The Great Spin Attack is learned after collecting all 20 stamps for Niko's Stamp Book.