To do an exceed accel you need to activate overdrive and during overdrive, activate it again, an easy way to do this is, go in the option and change your button layout, go to A+B+C+D and put this to R3, now when in a fight, when you push R3 to activate overdrive, hold it and it will go straight in exceed accel(a special move)
You can mix this trophy with the 10 overdrive finish, make sure when you use your exceed accel your opponent as low health to finish him with it and it will do an overdrive finish.