Keep your elbows close to your torso at all times and, without moving your upper arms, curl the weights while contracting your biceps.
Continue to raise the weight until your biceps are fully contracted and the bar is at shoulder level.
Hold the contracted position for a brief pause as you squeeze your biceps.
Slowly begin to bring the bar back to the starting position as your breathe in, ensuring to keep the movement controlled and not allowing the weight to drop quickly.