Weegee Time
It might be helpful to have Zeromus's attack algorithm and which version of the game you're playing. I'm no expert on the game, but the more information available, the better the odds of coming up with a strategy.
JP battle and algorithm: http://www.youtube.com/watch?v=_0bEjXuVFC4
NA battle: http://www.youtube.com/watch?v=BYWmwNWNP1A