I'd like to build a better training regime. I like super setting opposing muscle groups, and training till failure.

I generally do this schedule while changing up the machine/training each time:

Day 1 - Biceps/Triceps/Forearms
Day 2 - Cardio
Day 3 - Legs
Day 4 - Chest/Back
Day 5 - Shoulders/Traps/Calves
Day 6 - Cardio

I normally do 3x 4 sets on different workouts, while doing supersets on all muscles (except calves and forearms that I leave till end of training) I sometimes don't finish my last set of machines as I make it my failure set. My reps are normally around 8-10, and 15 for legs.

My goal is to build round, defined mass. What kind of change can you sggest for me?