Obviously, you need to practice fighting with other pirates before challenging the Sword Master.
Fortunately, a lot of would-be sword-fighters (labeled Ugly Pirate, Stinky Pirate, Bloodthirsty Pirate, Dirty-Rotten Pirate, etc.) are wandering the many paths on the general map of Melee Island.
To gain experience, why don't you fight them?
Let them bump into you on the road, and then challenge them to a duel.
Insult and response skills are key. Your sword-fighting abilities really don't matter.
Test your own insults, and learn some more from them. Be sure to figure out the right replies by testing insults on the pirates.
When you answer an insult correctly or give a pirate an insult he cannot respond to, you will step forward. Otherwise, you will step backwards.
When the pirates say you're ready to duel the Sword Master, find her and challenge her. You may not win immediately, as you may still have to learn some more insults and replies from the basic pirates. They don't know the replies to her insults, though -- you have to figure those out on your own.