The most important thing in MD is that you have to give at least 100% out of you when training. You don't need many sets to do this, 2-3 sets per bodypart will do the job if the sets are done in the all-out-way. As Dorian Yates has said: "One set per bodypart is enough but because we don't live in a perfect world and our workouts aren't always perfect it may be good to take two sets per bodypart."
At the beginning it's likely enough to carry your sets to positive failure which means you simply cannot lift the weight up by yourself, but on intermediate and advanced level you are able to carry your set beyond failure by using drops, forced reps, rest/pause, negatives etc. In a drop set your training partner decreases the weight when you cannot lift by yourself anymore. Forced reps mean that your partner gives you a hand when reached the positive failure. Rest/Pause means that when you have reached the positive failure you rest for about 15 secs and then try to get a few reps more. Negative reps/sets are very effective. In negatives you only work on the negative phase and your partner does the positive. In this way you can use more weight because the negative part of any movement is about 30 percent stronger than the positive.
You must also use such movements that allow you to use maximum amount of weight so forget those sissy movements and rely on heavy compound movements like bench press, leg press, squat, deadlift, barbell row etc.
The second and almost as important as the first one is the recuperation. When training hard you have to give yourself time to rest between workout to repair the broken muscle tissue and to grow. It may sound wild but as a thumb rule I would say that NEVER workout on consecutively days. A two-day rest between workouts would be suitable and by using a three day split, where the whole body is trained in three parts, a single bodypart gets 8 days rest. Too much rest isn't as bad as too little rest, remember that!
The third important thing is supplementation. Remember to get enough proteins and carbs so your progress won't halt because of a bad supplementation. You can calculate your need of proteins by multiplying your current weight by 1.5. This will give the amount of needed proteins in grams per day. If you can't get this amount then you can give up the whole thing, you don't have possibilities to gain muscle mass.
Carbohydrates, carbs, are 'the power source' of your training. In a good diet there are about 65% carbs. Remember to get a lot of carbs before and after a workout.
Today's food contains so much fat that you really don't need it anymore than that in food. The lesser the better!
This was only a brief overview of Mega Duty but if you are interested to know more about it, buy the book (K.P. Ourama: Mega Duty Kehonrakennusmenetelma).
