Clean and press

Stand with your feet shoulder-width apart and grip the barbell just outside your knees with your hips down and chest up.
Explode upward by driving through your heels and shrugging your shoulders to pull the bar vertically.
Quickly drop under the bar and catch it on the front of your shoulders (front rack position) with your elbows pointing forward.
Press the bar directly overhead until your arms are fully locked out and your head is slightly forward.
Lower the bar back to your shoulders and then to the floor in a controlled motion to reset.

Tips

At the start of the pull, keep the bar close to your body as it travels upward so that the momentum transfers directly into the catch.
When catching the bar in the front rack position, drive your elbows forward and up quickly so the bar rests on your shoulders rather than being held up by your hands.
During the overhead press, move your head slightly forward as the bar passes your face so the bar travels in a straight vertical path.

Using only an arm pull instead of driving through the legs and shrugging at the top causes the bar to lose height before the catch.
Catching the bar with the elbows low or pointing downward means the bar sits in the hands rather than resting on the shoulders, making the front rack position unstable.
Pressing the bar forward rather than straight up causes the bar path to drift away from vertical and the torso to lean back to compensate.