Phantom Breaker

When playing the story mode your gameplay settings will be reset to default, this means that the difficulty will be set to normal. This makes the process slightly more annoying than clearing arcade mode, however you can still make it through with a basic understanding of the game. A few things worth noting...

1.) When the meter on the bottom portion of your screen reaches 200% you should definitely attempt using the "Ultra deadly technique". You can do this quickly by pressing LT on default controls. It should do a fairly powerful move that can easily keep you in the fight if done correctly.

2.) Properly using overdrive. When you press RT you enter a state called overdrive. Your health will recover and your opponent will be slowed down thus giving you a chance to hit them for some decent damage. This is good if the opponent is starting to whittle your health down and you'd rather have the health than do the large chunk of damage with the Ultra Deadly Technique.

3.) This one doesn't pertain to fights themselves, however it drastically speeds the process. Hold the back button during the walls of text between battles to scroll through it quickly. Unless you speak Japanese and want to read the story, in that case...enjoy.

Those are just a few generic tips to help you though the game. When it came down to using Mikoto, I noticed that her simple Y,Y,Y string and dashing B attacks were good. She's also got a projectile she can use that is Forward + A which is fairly decent.