The Front Squat Setup. Like with Back Squats, your body is supposed to hold the bar not your hands. On Front Squats this means you should keep your chest up at all times so your shoulders support the barbell, not your wrists. If you try to support the weight with your hands, it will hurt. Chest up, elbows high, open hands. Don't hesistate stretching your wrists and triceps if you lack flexibility.
Foot Stance. Stance should be slightly wider than on the low bar Back Squat. Start with shoulder-with stance, go a bit wider.
Toes Out. How much depends on your foot stance, but they should always point in the same direction as your knees. So 30-45° out.
Chest Up. Put your chest forward and lift it up. This gives the bar a solid base to sit on & makes it impossible to round your upper-back.
Tighten Lats. You can't tighten your upper-back on Front Squats like on Squats. However you can tighten your lats: spread them.
Look Forward. Up is bad for your neck, down will make your lower back round. Look forward, fix a point in front of you.
Bar Position. Behind your clavicles and close to your throat. Coughing is possible and clavicles may hurt. Front Squat more, you'll adapt.
Hands Open. Your shoulders support the weight, not your hands. Open your hands, relax them. Three fingers under the bar is okay.
Elbows Up. Put your elbows up with your upper-arms almost parallel to the floor so the weight doesn't end up hurting your wrists.
Elbow In. Push your elbows toward each other during the Front Squat. This will be easier on your wrists.