Choose appropriate weights matching your fitness level. Take a shoulder-width stance and grab the dumbbells, letting them hang at arm’s length. Firm up your torso with pelvis in a neutral position.
From the starting position contract your upper trapezius muscles, elevating your shoulders (lifting arms upwards). Exhale while making the upwards motion and return to the starting position while inhaling. Do the required number of repetitions.
Watch for the correct starting position. Fix the thoracic muscles and the position of your pelvis to avoid lumbodorsal swayback and undesired backwards bending.
Choose the appropriate weight taking account of your fitness level. Exercise in front of a mirror to make sure you are using the correct technique.