Clean

Stand with your feet under your hips and grip the barbell with an overhand grip just outside your shoulders. Start with your back flat and chest up.
Drive through your legs to lift the bar. As it passes your knees, explosively extend your hips and shrug your shoulders to propel the bar upward.
As the bar becomes weightless, quickly pull your body under the bar, dropping into a full front squat to catch it in the front rack position on your shoulders.
From the bottom of the squat, drive through your feet to stand up straight, completing the lift.

Tips

Keep the bar close to your body throughout the pull so it travels in a nearly vertical path from the floor to the catch.
Time the shrug and elbow drive together so your elbows rotate forward quickly to secure the bar in the front rack position before you reach the bottom of the squat.
In the front rack position, keep your elbows high so the bar rests on your shoulders rather than being supported by your hands and wrists.

Pulling with the arms too early, before the hips have fully extended, reduces the upward momentum the bar receives from the lower body.
Letting the hips rise faster than the shoulders at the start of the pull causes the torso to become too horizontal before the bar reaches the knees.
Catching the bar with the elbows low forces the wrists to bear the weight of the bar instead of the shoulders, making the front rack position unstable.