Stand straight with a slight bend in the knees with the bar over mid foot.
Hinge and extend up to straighten your body.
Hinge and lower back down to the start position.
Arching the back.
Bending the knees too far forward.
Rushing repetitions.
Have the barbell set up at just above knee height. Standing with your feet spaced at shoulder width grip the bar with an overhand grip at slightly wider than shoulder width.
Start by bracing your core and drive through the heels to extend your hips and knees. Once at full extension, in a controlled manner lower the bar back down. As you pull up, squeeze your shoulder blades together to keep your shoulders square. Your elbows should remain close to your sides throughout. Repeat for the desired repetitions.
Avoid rounding the back.