This Trophy is easier than it looks, it has to be done in story mode however which isn't a big deal. You don't have to worry about score or keeping combo's going, just make sure to hit every note that comes your way and you should be fine. Turning the difficulty down to easy and picking a slower song will obviously increase your chances.
A good song that has a repetitive beat and easy to hit enemies and is quite short is
Blue Stahli - Takedown (One of my favourite tracks