This shrugs exercise is great for targeting the traps using only a pair of dumbbells.
Steps
Stand with your feet roughly shoulder width apart. Bend your knees slightly to take any pressure of them. Grip a dumbbell in each hand with your palms facing in towards your body. Lower your shoulders as much as possible. Keep your arms straight and slowly raise your shoulders up towards your ears.
Hold this position for a moment then slowly lower the dumbbells to their original position.
Tips
It may be tempting to use a jerking, swinging motion with this exercise. Avoid this temptation and focus on doing this exercise slowly. This will make the shrugs far more effective.