Dont forget the rest periods in between are just as important as the reps. I started with 4 sets of 8 reps with 30 seconds rest (im trying to build muscle and tone up) You can have longer rest periods for heavier weights tho. Now I do circuit training where I jump rope for the 30 seconds 'rest' period and add on another 15 seconds real rest.
After these workouts though its hard to even drive home or lift your hand