How do you get the most out of a workout?

for strength-low reps, high weight (i recommend a 5 by 5 program)
for muscle mass-med. reps, med. weight (8-12 reps)
for endurance-15+reps

make sure your workout is between 30-60 min(45 is best) not including cardio and stretching

make sure you eat after a workout. this replenishes your body's supply of nutrients and helps your body recuperate.