Focus on major muscle groups like your thighs, back, neck, and shoulders. Make sure not to bounce, and aim for about 30 seconds per stretch. Remember that stretching should never hurt. If something starts to hurt, stop right away. Try stretching after you wake up or anytime you need some energy. And try to stretch at least 2 to 3 times per week. Stretch after your workouts to reap the most benefits. Make sure to talk with your doctor before starting any new fitness routine.