How to properly perform a dumbbell chest fly exercise for maximum effectiveness?

To properly perform a dumbbell chest fly exercise for maximum effectiveness, lie on a flat bench with a dumbbell in each hand. Extend your arms above your chest with a slight bend in your elbows. Lower the weights out to the sides in a wide arc, keeping a slight bend in your elbows. Stop when your arms are parallel to the ground, then bring the weights back up to the starting position. Focus on squeezing your chest muscles throughout the movement for maximum effectiveness.