1.Exercise properly using good form,intensity and allow enough time
between workouts for recovery.

2.Be on a positive caloric intake.

3.Spread your daily calories out over 5-6 meals a day.

4.Supplement with proven supplements like:
Protein (1 gram per pound of lean body weight per day),multi-
vitamin,omega-3,amino acids and creatine.
(Be sure to take your multi-vitamin with food or your body will not
absorb it properly)

5.Drink plenty of water (Around a gallon a day for most).