Deadlift

Preparation
Place the barbell on the floor within the range of your feet, close to your toes. Take a stance slightly narrower than your shoulders. Bend down and grip the bar, so that your palms are directly under your shoulders. Use a mixed grip-one overhand one underhand instead of double overhand. Push your pelvis backward, trying to keep your knees and shoulders above your heels. Push your butt back and bring it down until your back is straight. Push your shoulders back: this way your back will form a straight line. Keep that line tight. Take a little bit of air into the stomach (not the lungs) and tighten your abdominal wall (as if preparing to take a punch) and hold it this way. Do not loosen your back, the abs or air while doing the exercise. You can only breathe when you are back up.

Movement up
Shoulders start going up, the rest of the body follows, while keeping the back in a straight line. The weight falls on the heels. Arms are tight, very much like lines on a boat. Make sure the bar follows the curve of your legs, you can even let it slide up. Make sure your knees don't go left or right, they must point to your toes. Once the bar is past your knees, push forward with your butt, draw your shoulders back and press the bar to your body, arms tight. Keep your balance, try not to swing backwards. Keep the imaginary line that connects your heels and your shoulders straight. Once up, don't push your chest out too much, just stand straight. You may want to take a little bit of air if you need to. Otherwise, take a breath at the bottom.

Movement down
The butt goes back and down, while knees don't go forward. The weight is on the heels. Try to stand as straight as possible, without bending in the waist. Your torso will shift forward a bit, just to keep balance. Let the barbell slide down following the natural curve of your legs. Once the barbell passes your knees, you go down in a controlled descend. Only when the barbell in on the floor, you can relax your abdominal muscles and breathe.