In many fanfictions, Ron's loyalty and love for Hermione play a big role. His determination to save her gives him an extra boost of courage. He might directly confront Draco, using his Gryffindor bravado. He could use a disarming spell to take Draco's wand and then quickly grab Hermione and run off to a safe place within the castle.
Well, in some versions, Ron might use his quick wit and knowledge of Hogwarts' secret passages to outmaneuver Draco. He could lead Hermione to safety through a passage that Draco doesn't know about.
Ron could also use his magic skills. Maybe he casts a powerful shield charm to protect Hermione from Draco's spells. He has been shown to be quite capable in combat magic, especially when it comes to protecting his friends. He might also summon some magical creatures to distract Draco while he gets Hermione away.