Choose an appropriate weight matching your fitness level. Your stance is a little wider than your shoulders. Grab the barbell with a pronated grip (palms facing down); your hands are in a balanced, shoulder-width position. Bend your knees slightly and bend your lower back as far that your torso remains upright without straining either your lower (lordosis) or your upper back (kyphosis); your pelvis is in a neutral position. Keep your torso perpendicular to the femur. Your arms are hanging freely.
Lift the barbell to the chest by flexing your elbows and contracting your middle back (scapular) muscles.
Keep your elbows close to your torso as you lift up the barbell (not sideways). Go back to the starting position in the same manner. Repeat as required. Breathe out as you go up; breathe in as you go down.
Make sure your stance is correct to avoid straining your lumbar lordosis (your lower back) and thoracic kyphosis (over-curvature of the upper back).
When you bend over, make sure the angle between femur and torso is around 90 degrees in both hips.
Your knees should not exceed the line of your toes.
Avoid uncontrolled elbow motion to the sides.
Make sure you eliminate use of the trapezius muscles.
Perform the exercise in front of the mirror and watch yourself to make sure you are using the right technique.
Choose your resistance to match your abilities and fitness level. Start with lighter resistance to master the technique well.
Bend your torso forwards, slightly bend your knees and keep your back stretched. Grab the barbell by overhand grip and lift it to your starting position. Then pull the barbell to your chest. Keep your head up during the whole set.
Retract your shoulder blades (scapular retraction) at the end of the pulling movement.
It should be said that this exercise puts much pressure on lower back, especially when using heavy weights. Therefore it is potentially more dangerous comparing to back exercises where you are using one hand as a support or those where your torso is leaning against a padded platform.