Keep your elbows close to your torso at all times, and make sure your upper arms are stationary throughout the exercise.
Now, curl the weights while contracting your biceps as you breathe out, only your forearms should move.
Continue the movement until your biceps are fully contracted and the barbell is at shoulder level, hold this contracted position for a second as you squeeze your biceps.
Slowly begin to bring the barbell back to the starting position as your breathe in, maintaining control and not letting the weight drop suddenly.
Pro Tip
Controlled Movement: Avoid swinging or using your back or shoulders to lift the weights. The movement should be controlled and originate from your biceps. Lift the barbell by contracting your biceps while keeping the rest of your body still. Full Range of Motion: Lower the barbell all the way down to fully extend your arms, and curl it all the way up to your shoulders to get a full range of motion. Half reps will not fully engage the biceps. Breathing Technique: Breathe out as you curl the barbell up and breathe in as you lower it. Proper breathing technique can help you perform the exercise more effectively.