3. Focus on Compound Exercises
Compound exercises recruit many more muscle fibers than isolation exercises, so you will gain more overall strength. Compound lifts are the easiest to make strength gains with, which obviously means faster muscle mass gains as well.
Sample Compound Exercises:
Chest: Flat Bench Press, Incline Bench Press, Decline Bench, Dips
Back: Pull-ups, Barbell Rows, Deadlifts
Legs: Barbell Squat, Stiff-Leg Deadlifts, Box Squats
Shoulders: Military Press, Standing Press, Seated Dumbbell Press