Deadlift

Stand with your feet shoulder-width apart, with the barbell over the middle of your feet. Hinge at your hips and bend your knees to grip the bar just outside your legs.
Keep your back straight, chest up, and look forward.
Take a deep breath to brace your core. Initiate the lift by driving through your heels and pushing the floor away.
Drive your hips forward and stand tall, squeezing your glutes at the top.
Lower the bar with control by pushing your hips back and bending your knees, returning it to the floor.

Tips

Before you pull, take a full breath into your belly and brace your trunk firmly so your torso angle stays fixed from the floor to mid-shin.
Keep the bar in contact with or very close to your legs throughout the entire lift, both on the way up and on the way down.
At the top, drive your hips fully forward until your hips and knees are locked out and your body is upright, then squeeze your glutes to complete the rep.

Rounding the lower back at the start of the pull, which means the neutral spine established at setup is lost before the bar leaves the floor.
Letting the hips rise faster than the shoulders at the start of the pull, so the torso becomes more horizontal and the lift turns into a stiff-leg pattern.
Allowing the bar to drift away from the body during the ascent, so it swings forward in an arc rather than traveling straight up.