A well balanced exercise program needs to include three major areas of fitness: Resistance or strength training, aerobic or cardio training and stretching or flexibility training.

Resistance (strength) training 20 minutes of resistance training with dumbells, barbells, body weight, resistance bands or using weight machines twice a week. All the major muscle groups of the legs, abdomen, arms, chest, back and shoulders should be worked.
Aerobic (cardio) training 30 minutes of exercise at about 60% to 85% of your maximum heart should be done at least 3 times per week, more often is best. The 60% to 85% is known as your the aerobic range, which is calculated by subtracting your age from 220, then multiplying that number by .60 and .85 to obtain your heart rate range. 
Stretching (flexibility) training 15 minutes of stretching, after you’re fully warmed up, to include all the major muscle groups at least 3 times per week.